Engine stalling problem

[bigdog]

Hi Folks,

Have a engine stalling problem which just can't seem to be resolved?

Problem is engine runs fine 'in the yard' with 'muffs' attached. I've run for more than 30 min. even up to 2500RPM without issues.

However,when I run boat in the water, it coughs, sputtters and stalls just about immediately, attempting to go more than wake-speed. Doesn't seem to run under a 'load', but appears to run fine idleing in the yard
'on the motor-muffs'.

I am using ethanol gas, which still has Sta-Bil and ValviTech treatment from
last season. I checked samples of gas, and all looks ok, doesn't look like any water in gas. Gas looks clear, no bubbles, or any type of foreign particles. The fuel/water separating filter has been changed-out twice. I changed spark plugs. Dealer has performed a coplete Carb rebuild. No difference in engine behavior? Dealer still thinks there's some water in the system. They have ruled out this being 'fuel pump related.

OK, if there still s some water in the gas it doesn't seem prevalent or obvious? I have 35 gal of gas in the tank now. If I have to drain it out and start with fresh, any siuggestions how I would go about doing this?
I'd have to have 7-8 five-gal cans, which is inpractical. Secondly, what am I suppose to do with this gas once drained? Dealer has not been very much help, and is not setup to handle this situation.

Would appreciate any suggestions about the gas question, or maybe comments about the engine behavior not being gas related.

At 'wits end' !!

[chipj29]

My snowmobile and PWC, which tend to sit for long periods of time in the off-season, run like crap at the beginning of the year. The gas with Sta-bil, ethanol and the other stuff just does not want to run well. I found that the ethanol + stabilizer combo just does not burn well at all. The ethanol has been murder on engines from what I have seen, especially the older gas.

If it were me, I would find a way to safely siphon out as much of that old gas as I could. Put in a nice batch of fresh gas...just gas, no additives (unless you need to mix in oil). Fire it up and rev it up a bit. After it runs for a little while, change your spark plugs as they may have fouled.

As for disposal of the old gas, I can't help you there. I have heard of people using that old gas in lawn mowers, and even in their cars. Not sure I would recommend that...

[Dave R]

The best way to rule out the gas as an issue is to rig up an auxilliary tank of gas and run it on that temporarily to see if the problem persists. Something like this: http://willardssmallengines.com/shop...-gas-tank.html would work. If you have a generator, roto-tiller, or some other small 4-stroke, engine powered device, with an easy to remove fuel tank, borrow it for the test.

[fatlazyless]

Cheap fix....a one dollar bottle of Wal-Mart carb/injector cleaner. Expensive fix....a six dollar bottle of Chevron Techron carb/injector cleaner. And keep your fingers crossed?

[Bear Islander]

One reason an engine will run poorly under load, but ok under no load is because it is not getting the extra fuel it needs. You said they checked the fuel pump but what about the fuel filter or some other restriction?

The timing also becomes more critical under load. If you don't have electronic ignition the timing could be off or not advancing as you accelerate.

Dave R's idea of using a seperate tank is a good one.

[Seeker]

Sounds to me like the octane rating in your gas has gone south. If your gas is really bad it should have a distinctive odor.

You're going to have to eliminate one thing at a time and Dave's suggestion is the best way to start. I am assuming it runs fine in neutral in the water and just starts acting up when under load. I once had a similar problem that turned out to be ignition related. If the fresh gas doesn't solve it look there. Good luck.

[gtxrider]

I had a trouble like yours and as FLL suggested in previous message try running fuel system cleaner through. I the dealer look at it and I alos cleaned the carbs and jets. That cured the trouble for a short time only to have it return. I added a bottle of fuel system cleaner and ran the motor and it slowly came back to life..

Also try the spare gas tank trick to rule out bad fuel.

GOOD LUCK!

[Tallyho]

You didn't mention the age of your motor, but I would check coils and wires for cracks. Running the engine in your driveway with muffs, is a lot drier environment, than when the boat is in the water. Putting a load on the engine under damp conditions might be just enough to cause a short to ground. I've had a similar problems in the past.

[ITD]

Check this out: http://www.bostonherald.com/business...ome&position=2

[robmac]

The problem could be different tjings depending upon engine? carb or inj.? age? if inj.could be as simple as a cable binding,carb a float stuck. Doesn't sound like fouled plugs because as you bring up the idle should hear and feel a missfire.Need more info on engine

[SAMIAM]

I vote with Bear....change the filter.

[sa meredith]

SAMIAM...maybe the good folks over at Whining Butcher could take a look at it???

[2Blackdogs]

Is the fuel line pinched?

(Occam's Razor).

[Rinkerfam]

I feel your frustration. I had the exact same problem with an older mercury outboard. I spent a lot of money on diagnostics, electronic ignition components, water impeller, primer bulb and flexible fuel line. Ultimately the problem was a seven dollar piece of copper tubing that came out of the fuel tank, and ran through the side of the transom where it was attached to the flex line and bulb. There was a ninety degree elbow where the line came through the hull and it had cracked there. It was a simple as that. I hope you find the cheap fix first!!

[bigdog]

Thanks for all the suggestions, much appreciated !

FYI as follows:
1995 4.3LX Mercruiser 220HP
Not electronic ignition

Again... engine runs fine 'out of water' even revving....

Marine mechanic performed following checks:
- Carb kit just installed (new jets, needles, springs, accel pump, etc)
- Carb float is metal not plaastic type.
This was not replaced with as part of rebuild kit. Tech said it was OK.
- Distributor cap and rotor OK
- Fuel pump, they said was OK, but not sure if tet performed?
- New plugs installed (by myself)
- Fuel/water filter replaced twice
- Coil cable looks good, but did no check perfomed on coil

Using an Aux. gas tank to test is a great idea, but doesn't look like it would be a simple adaptation hookup, between tank and gas line feed?

Going to siphon out as much gas as I can, and replace with fresh gas.
Adding some more Gas line water remover treatment, and maybe some octane booster. Can't hurt at this point !

If this fails, going to contact another marine dealer to see if they can perform gas removal and discard old gas ? TBD?

My guess is that all systems are OK, and the 'ethanol' gas is the culprit !

Thanks again!
Bigdog

[WakeUp]

Bigdog:

Go to any NAPA and ask for "Seafoam." This stuff is beyond belief. Developed over 50 years ago for tha marine industry, it's now available at the retail level. To quote the manager of NAPA: "I could get rid of every other product in here and just keep Seafoam...I always keep half dozen bottles at home." It's even better than the Lucas products...hope it's helpful

[Dave R]

Originally Posted by bigdog

Using an Aux. gas tank to test is a great idea, but doesn't look like it would be a simple adaptation hookup, between tank and gas line feed?

Bigdog

You'd want it just upstream of the fuel pump. This will eliminate the entire fuel tank/lines and the fuel filter, and feed known-good fuel directly to the carburetor.

Fuel hose replacement is conspicuously absent form your list of things done. It's cheap and easy.

[Sman]

When running your engine out of water, are you running water through the engine to cool it?
Is is running long enough that you see it spitting out of your exhaust?

Maybe someone more mechanically inclined could comment on this thought...

If you had a crack in your exhaust manifold jacket, you would not necessarily see it and it might cause problems where water could get into the engine. If you are running your engine out of water, not hooked up to water or it is not being run long enough for the water to run through the system or to build up adequate pressure to cause a problem it would always run good out of water, (if that was the problem)

I had a crack in my exhaust manifold on the exterior and it would leak water when under way, I replaced it at not much cost or trouble myself, I was told a crack on the inside of the jacket would have been worse.

Or it could be some other cooling system related issue where there is a leak, where water is going somewhere it should not.

[Sman]

Problem is engine runs fine 'in the yard' with 'muffs' attached. I've run for more than 30 min. even up to 2500RPM without issues.

not sure my idea still applies unless out of water at 2500 rpms is very different than in the water at 2500 rpms...

[Woodsy]

When exactly did this problem start??

Essentially your motor starts breaking down under load. This would tell me that there is an ignition or fuel delivery problem somewhere.

I seriously doubt a 95 V6 has points & condenser, so to clarify... you do have an electronic ignition.

The fuel side is an easy test.... attach a pressure gauge in-line before the carb.... splash boat, check fuel pressure!

The ignition side is a bit trickier. But I have my suspicions!

Step 1: You said YOU changed the spark plugs. I would check them to make sure you didnt crack one installing them. Pull each one out one at a time and thoroughly inspect the plug. Note the color of the electrode on each plug. Any plug that looks signifigantly different from the rest might indicate a problem with that cylinder....


Step 2: When was the last time your ignition wires were replaced? I think these are the most likely culprit! The insulation on those breaks down over time, especially in a moist marine environment. You might have inadvertantly cracked a wire when you installed the spark plugs.... Replace each wire individually so as not to screw up the firing order. Double check that you didnt screw up the firing order when you changed the plugs the first time.


Hope this helps...

Woodsy

[bigdog]

OK, here's the latest update.

Marine dealer can pump out old gas, but has no means to dispose of fuel.
Consequently, I would have to supply enough containers to hold 35 gal of fuel. Went to local automotive repair shop with same question, got same answer.

As I may not be able to remove old gas, I may just have to keep running until the level gets down to where I can add new fresh gas.

In the meantime I'm going to remove water seaparating filter and keep dumping fuel after running for 15 min each time. Again, after already doing this several times there is no apparent inidcation of water in the fuel.
Also have added gas additive to remove any water (HEAT), and also added an octane booster. I suspect gas looses it's properties when sitting over long periods of time.

To answer a previous comment, I am running plenty of water through the engine, and can see it coming out the ports of outdrive where it should be.
Engine temp.reamins to stay low.

Going to purchase a new fuel line hose, to connect from tank to fuel pump,
BTW is electric. Should be a inexpensive replacement.

To answer another question about the plug/coil ignition wires, not sure if these have ever been changed. Boat is 13 yrs old and engine only has 160hrs believe it or not.... Wires look like new, but I guess youcan't tell the inside condition of wires from outside appearances. Will see if NAPA dealer
has a replacement. Can't hurt to replace... Right?

Also, I believe engine only has a rotor, no condensor or points.

Suggestion to perform a fuel pump check presure check, I would have to bring back to marine mechanic. Surprised they didn't do this as SOP. Sound like it was too much trouble for them ?

One last question which nobody suggested.... Could I have a bad Coil, and would that exhibit this type of engine behavior?

Thanks again.
Bigdog

[Woodsy]

BigDog...


DEFINITELY replace the cap, rotor, wires & check the plugs you put in. 13 year old wires (regardless of usage) are pretty much junk! If you inspect the Cap, rotor & wires closely you will prob see signs of carbon scoring... Make sure you do this one at a time and double check the firing order BEFORE and AFTER you finish.... I cant stress that enough!

Its possible you have a bad coil.... similar symptoms. but change the wires first. I think the wires are arcing out...

I wouldnt worry too much about the gas.... when you change your fuel water separator, dump the gas into a clear glass container and cover. Let it sit for a few days... if there is water in the gas you will see it.

Just keep adding new gas to the current gas. Go to Y-Landing and spend the $$$ on the Hi-test... Hi-test mixed with Junk usually yields a decent enough mixture.

Woodsy

[2Blackdogs]

Originally Posted by bigdog

Boat is 13 yrs old and engine only has 160hrs believe it or not.... Wires look like new, but I guess youcan't tell the inside condition of wires from outside appearances. Will see if NAPA dealer
has a replacement. Can't hurt to replace... Right?

A set of wires 12 years old worked, but a year later, won't? I don't think it's the wires, because the engine would misfire at an idle, which isn't your problem. But here's a test anyway.

The easiest way to check plug wires is to run the engine in complete darkness and watch.

Throw an opaque tarp over the engine area at night to get rid of any extra light, and allow lots of time for your eyes to adjust to the darkness. This test is not effective if there's ANY light around. Tonight there will be no moonlight.

Failing wires will provide a real light show, sending sparks out to anything nearby, even the other plug wires! Watch the area at the coil for sparks there. You can vary the speed, but any sparks indicative of wire failure will be apparent even at an idle. Note the location of nearby turning or hot accessories which could present a hazard in darkness.

Ignition manufacturers once marketed a transparent distributor cap. It might have been boring to watch the sparks after a time, but it was an interesting idea.

[Woodsy]

2BlackDogs...

You might have a point if the wires were undisturbed.... However he changed the spark plugs. In order to change the plugs the wires need to be removed and flexed around.... this will cause cracks to form in the 13yr old silicone allowing the wires to ground out. Its also quite possible the firing order was screwed up as well when he put it back together.

The firing order is 1-6-5-4-3-2

As far as the wires causing a misfire at idle or unloaded... the misfire is probably still there, however the motor isnt under load, so it is alot less noticable. If you really want to get into specifics you can take an ohm meter to each wire and measure the resistance... You are looking for approximately 600 ohms/ft resistance. Less resistance is better! If the wire is bad you will usually see a reading ALOT higher.

No need for the tarp/dark weather voodoo testing method!

There isnt really any great test for the coil... when idling (unloaded) on the hose its going to take along time for a coil to get hot & malfunction vs. an almost immeadiate malfunction under load. If the motor runs great for 20 -30 minutes or so on the hose, then misfires & dies.... its quite possibly the coil


Woodsy

[bigdog]

Two Black Dogs, great idea to check the ignition wires, will do tonight!

However.....
Woodsy you may have unravelled this mystery when you stated
'If the motor runs great for 20 -30 minutes or so on the hose, then misfires & dies.... its quite possibly the coil'

I have been running the engine on the hose for 20-30 and seems to run fine, real smooth, even rev-it to 2200RPM without issues...... Then about the 25-30 minute mark, it starts to mis-fire & dies !!!! Exactly as Woodsy stated !

Could it be the coil heating up, then mal-functioning ? One could only hope !
Could be just the coil wire, and not the coil, or maybe both?

As a few have stated, there's no real way to tell if the coil is bad?
How much do these little buggers cost ?

Still going to try wire night-test to check wires.

All comments appreciated !

Thanks,
Bigdog

[2Blackdogs]

Originally Posted by Woodsy

You might have a point if the wires were undisturbed.... However he changed the spark plugs.

The plugs were changed in response to poor performance, or, to put it another way, the problem appeared *before* the plugs were changed.

Except in air-cooled applications, silicone wires have exceptional longevity. The wires may be 13 years old, but the engine has 160 hours on it. I put that many hours on the lake in one summer.

And actually, there is a way to check a coil. Snap-On and MAC sell relatively inexpensive coil testers, and there are probably far cheaper testers on the market today. You just dial in the suspect coil to the point of spark failure, and the analog dial will advise if the coil is marginal or not. I'm not advising that bigdog go buy one, however. Use of darkness to pinpoint an ignition problem IS worthwhile and costs nothing. Humidity, like we had yesterday, increases the effects.

As for the old gas, it can be put in proper containers and sold to those who would mix it with fresh gas. The cost of new containers can be recouped when the old gas is sold. With those additives, I doubt that the gas is so bad that it can't be used as normal. Even then, it can be added in increments to a near-full tank on a truck, lawn mower or the older 2-stroke outboards, which have a great tolerance for old gas mixes.

[Woodsy]

2BlackDogs...

There is a big difference between "poor performance" and outright not running! BigDog did not state that he changed the plugs as a result of this problem occurring. I was under the assumption that he changed the plugs due to routine maintenance and the not running problem appeared right after.

Woodsy

[Dave R]

Originally Posted by bigdog

Two Black Dogs, great idea to check the ignition wires, will do tonight!

However.....
Woodsy you may have unravelled this mystery when you stated
'If the motor runs great for 20 -30 minutes or so on the hose, then misfires & dies.... its quite possibly the coil'

I have been running the engine on the hose for 20-30 and seems to run fine, real smooth, even rev-it to 2200RPM without issues...... Then about the 25-30 minute mark, it starts to mis-fire & dies !!!! Exactly as Woodsy stated !

Could it be the coil heating up, then mal-functioning ? One could only hope !
Could be just the coil wire, and not the coil, or maybe both?

As a few have stated, there's no real way to tell if the coil is bad?
How much do these little buggers cost ?

Still going to try wire night-test to check wires.

All comments appreciated !

Thanks,
Bigdog

You can check the coil with an ohm meter and a toaster oven. Measure the resistance from - terminal to the high voltage output cold, then heat the coil up to 200 degrees and measure again. Should be little difference. That said, a new one is like 28 bucks from Napa (Sierra part number L47-5433 is liekly what you need).

[Audiofn]

Did you ever figure this out? Just currious what it was!! I hope so!!

Jon

[John A. Birdsall]

I use gas with ethanol in it and last year I put that Stabil stuff in the tank. I had probems with it this year. I have an 115 Evinerude and use two six gallon tanks. I took one tank of fresh gas/oil mix and it worked great, so after it got running I switched back to the old gas. I finally burnt the old gas up, but it would not start good on that tank. Till I put fresh gas in it. Waste not want not With a built in tank you would have to find a way to do this.

[Jersey Joe]

Did you ever find the problem. I have a 92 four winns, OMC, 5.0, Carb. My boat will run perfectly for hours, then just stall out at cruising speed. 1st time, we were running for about 2 hours, and boat seemed to run out of gas, restarted it, and it would only idle. Then died completely. I played around with the upper fuel filter and she re-started and ran perfectly for another hour.

I got home, changed seperator, cleaned upper filter (it is only a screen) and added some stabilizer to the gas.

Took the boat our Sunday. (we run on the Hudson River down here in New Jersey). We did a 60 Mile Run up the river. About 55 miles into the ride, less than 5 miles from the marina (right in front of the Indian Point Nuclear Reactor for anybody that knows the area) running along at about 25 knots and same thing. Just died, like it was runnning out of gas. This is after almost 3 hours of running. Started it up, and it would only run up to about 1400 - 1500 RPM, but then after about 5 - 7 minutes, Died Out again. I took a wrench and tapped the fuel line by the upper filter (screen) and she started up and ran like a champ. However at that point, the water was getting rough and I did not want to chance another stall.

So, any thoughts ? Could it be dirt in the tank that gets sucked up after a few hours of running? Could the float in the carb be hanging up, then when I fool around it drops back. Why would it run flawlessly for hours and hours, then die?

I am at a loss. Anybody want to buy the boat, it is getting that frustrating.

[Toyorelle]

Originally Posted by Jersey Joe

Did you ever find the problem. I have a 92 four winns, OMC, 5.0, Carb. My boat will run perfectly for hours, then just stall out at cruising speed. 1st time, we were running for about 2 hours, and boat seemed to run out of gas, restarted it, and it would only idle. Then died completely. I played around with the upper fuel filter and she re-started and ran perfectly for another hour.

I got home, changed seperator, cleaned upper filter (it is only a screen) and added some stabilizer to the gas.

Took the boat our Sunday. (we run on the Hudson River down here in New Jersey). We did a 60 Mile Run up the river. About 55 miles into the ride, less than 5 miles from the marina (right in front of the Indian Point Nuclear Reactor for anybody that knows the area) running along at about 25 knots and same thing. Just died, like it was runnning out of gas. This is after almost 3 hours of running. Started it up, and it would only run up to about 1400 - 1500 RPM, but then after about 5 - 7 minutes, Died Out again. I took a wrench and tapped the fuel line by the upper filter (screen) and she started up and ran like a champ. However at that point, the water was getting rough and I did not want to chance another stall.

So, any thoughts ? Could it be dirt in the tank that gets sucked up after a few hours of running? Could the float in the carb be hanging up, then when I fool around it drops back. Why would it run flawlessly for hours and hours, then die?

I am at a loss. Anybody want to buy the boat, it is getting that frustrating.

Did you check the carb for condensation? I ran into that issue a couple years back on my old boat. The condensation would build up and it would run fine for a while but then stall out.

[Jersey Joe]

No, but I will try anything. We put the boat away for the winter, and before so I had my mechanic look it over. He could not come up with anything. Only thing he suggested was the coil, perhaps after a very long run, the coil begins to fail ? But I think it is more fuel related. Oh well, the wrap is on and we will start over again in the spring.

Thanks for the reply

[robmac]

Hate to beat a dead horse but I think checking the simple things will always be more eficient and cost affective that tossing darts at the problem.I would purchase a spark test lead ( most prts stores for less than $ 10.00 ) put it on a plug then plug the wire for that cylinder and run the engine till it stalls. You will then be able to safely crank the engine and verify wether or not you have spark and go from there.

[southerncomfort]

u may want to check your fuel lines the gas with ethanol will eat the rubber lines from the in side. on boats older than 2000. also fuel pump diaphragm gets weak and this will cause the boat to stall as fuel line closes up because it gets weak

[bigdog]

Hi....

My engine stalling problem, has reared it's ugly head again today !
Thought I had this problem cured, guess not.

At the beginning of the season, at the advise of 'JST_4_KIKS', I completely drained my gas tank, all 35 gallons. (BTW, I used all this gas in 3 different cars, without any issues).

I then filled tank with 89 Octane, and added a can of 'Seafoam'. Because of the lousy weather this summer I've only been able to get boat on water a couple of times. On each occasion, we only ran the boat out for about 30 minutes, during which we usually take a swim, have lunch, then return to
to the boat ramp. Only ran the boat around half-speed, but seemed to run smooth w/o stalling, coughing, or backfiring.

Well, today I took boat out for a short run. We ran boat for only about
15 min did our routine (lunch and swim), then pulled anchor to take a short ride. After a couple minutes the boat started to cough sputter, and backfire, and I started to loose power. Turned boat around and headed back to boat ramp. Got back to ramp ok, but stalled twice in lesss than 1/4 mile.
Pulled boat out and parked boat back in yard.

I immediately got on the phone to the marine techs, the same which just replaced all my bellows and trim senders. Just picked up the boat Saturday !

Anyway, they had performed a complete Carb rebuild last season, because I had this same stalling problem back then. They said to me at the time that this was the problem, and probably caused by the ethanol gas, and have seen this issue many times with other customers. BTW, they didn't at the time test for any other causes, they just did the Card rebuild. Trusting their experience and knowledge I let them go ahead with the job, $300 !

After this was done, I only had one opportunity to use the boat before the end of last season. Again we probably only used for 30 minutes, 15 mi to get to our destination and 15 back ! It seemed to run OK, at least it didn't stall.

Today the marine techs, said it sounded to be spark related issue, and may be Distributor Cap, Rotor and/or Timing? Sounds like at this point they may just be guessing?

Again, I can run the engine in my yard on the motor-muffs forever, without the engine stalling, or backfiring. And rev-it without hesitation.

Very Frustrated and just want to get to the bottom of the problem, so I can spend some quality time boating with what's left of the summer.

Your comments and suggestions are appreciated.

Thanks,
Bigdog

[Winnipesaukee]

From your symptoms I'd say it's a fuel issue. Check your fuel pump.

After this happens again, check for fuel pressure (find the schrader valve and depress it. Does fuel spurt out?

I'm thinking something might also be wrong with your float valve. Give the top of the carb a good whack the next time you stall out.

[Airwaves]

Winnipesaukee is right about the float value, I had that problem with our I/O and it got it running again, although if you had the carb rebuilt last year I wouldn't think it should be a problem this soon...but give it a shot.

The other thing it could be is the water separator needs to be changed out. When they become full of water or sludge the engine tends to bog down and die. Cleaning out a fuel tank is not an easy thing to do and you could have easily missed some sludge or water.

The other thing to do with ethanol in the fuel is to keep your tank full. If you run for a half hour or so you've probably burned several gallons of fuel and that will leave room for condensation to form. I have read it only takes a couple of weeks for the phase separation to begin and once that happens there is water/sludge in the tank again. (If you put it away last fall and it wasn't completely topped off then it attracted moisture over the winter)

I have never tried Seafoam, Startron got my engine at least running again and this year I am running StaBil formulated for ethanol on the recommendation of the marina. It claims to prevent corrosion of aluminum fuel tanks as well as everthing else ethanol related.

Replace the fuel filter as well.

As far as being able to run it in your yard okay that wouldn't be unusual since the fuel problem will show up when you try operate it under load. It uses more fuel then and sucks in the bad stuff in greater quantities.

If all you paid for the carb rebuild was $300 you got off cheap! I had to have the 4 carbs on my 115 Merc Outboard rebuilt and it was just under $740!

Good luck

[robmac]

It sounds to me to be an ignition related issue. Carb would be a constant happening where as ignition can come on with added heat from running and will tend to be intermittant. I would start by taking a spray bottle while running the engine on muffs and misting the cap and then the wires looking for the engine to stumble. If nothing changes then remove the cap and check for corosion on the contacts and rotor as well as the pick up. Hope that gives you a little help,keep us informed.

[bigdog]

Here's the latest update....

Spoke with marine mechanic about my engine stalling, backfiring problem
and he thought 'ignition problem'. This is the same marine tech who performed Carb rebuild last July to supposedly correct this issue.
The Carb rebuild was definitely needed, however never really corrected the initial problem.

I personally don't think it's a engine fuel problem, because of the 'back-firing'.
I don't think fuel starvation would cause this type of behavior? A bad fuel pump, would stop fuel delivery, but I don't believe would cause 'back-firing'
Maybe someone can comment on this !

Mechanic said bring boat back to him and he'll work with me to correct.
Now thinking he'll replace Distributor Cap and Rotor. He has had several boats come into shop recently with same symptoms, and after checking
Distributor cap and Rotor, found corrosion in all cases.

I have never replaced same myself, and the second owner. Have had boat
3 seasons, but only put maybe 100 hrs on boat. Not sure when previous owner replaced these parts before or ever ? Could potentially be the culprit for this issue, but bad Coil could also be the problem. Right now it's
basically the process of elimination, starting with the least expensive items first, and working up from there !

'2BlackDogs' suggested checking the ignition wires in darkness and that if the ignit. wires, Coil, etc were arcing this would definitely be obvious, and provide a light-show ! Well, tonight in complete darkness, I mean I couldn't see my hand in front of my face, I started up the engine, and could not see any spark arcing coming from ignition wires, Distributor, or Coil.
Nada, zip, nothing ! If anything was spark/arcing it was not visible.

Will keep Forum informaed about progress. IT WILL BE FIXED !
But my wallet may be empty........

Bigdog

[robmac]

BD, even though you didn't see arching you weren't under load, that's why I suggested misting w/water. We do that test all the time because techs work during the day and prefer to eliminate problems rather than empty your wallet.

[Winnipesaukee]

Funny, just today I came across a weekend car with similar symptoms. A mechanic I work with said varnish started to form in the fuel lines, AFTER the filter, and backed up the injectors, causing the same problem.

You could be having the same issue, especially now that ethanol is in your gas. Each time you store the boat, the fuel in the line will go bad and varnish. When the boat is started, the varnish before the filter flows into it, clogging it, AND the varnish after the filter goes into the carb where it bottlenecks, killing your engine mid-trip.

Not sure if you have yet, but dump some Seafoam in your gas tank and run the engine. Make sure you have fresh fuel/water filters.


....

A failing head gasket might also cause the same symptoms. You can't compress/burn water efficiently.

[bigdog]

Winnipesaukee, FYI I had totally drained my gastank, refilled with fresh 89 Octane gas, new fuel/separting filter, and added a can of Seafom at the recommendation of 'Jst_4_Kiks' (he's a Marine Tech).


Boat ran fine 1st time out this season, second time started this issue again. Engine seems like it's not gettting the gas, with stalling, however with the back-firing
symptoms, it seems to point to an ignition related problem to me. 'Jst_4_Kiks' seems to concur.

Boat at marine repair shop now. Having them check Distributor Cap, Rotor.
Both are probably orginal, at least I have not changed out since I owned boat (3 yrs). Boat is 1995, not sure what original owner did?

Your comments are greatly appreciated !

Bigdog

[macshpman]

I had a friend with a boat that his vent line to the fuel tank had become plugged by a insect building his home inside the line. The tank would build a vacuum causing the fuel system to lean out, and stalling backfire would be the signs of the trouble. It would act differently depending on the amount of fuel in the tank and how long and hard he ran the engine. Its worth looking into for sure. He chased this problem for a summer and was changing parts like he was changing his clothes. Very frustrating for him to not be able run 30 miles out from shore to do his fishing and not sure if he was going to be able to make it out and then back in.

[bigdog]

Thanks MacShpMan for info about vent hose blockage. I have checked
hose at the top where it eixts the boat, however, have not checked
entire length of hose. Not sure how one would do that, or how to clean out.
Suppose I could run some plastic tubing down through the vent hose to check for obstructions, but then again don't want to force anything down
furhter if something is there....

I can relate to your friend's boat problems. I feel like I'm changing parts like clothes !

Talked to marine tech. this morning, he didn't have a chance to replace Distributor Cap or Rotor Friday because of backlog of customer repairs.
He's going to order parts Monday and work on boat Tuesday. After parts installed he said he'll take to nearby pond to test, best he can do under the conditions. I plan to be on that ride myself !

Marine Tech said it may be Carb problems again, but I reminded him the Carb about the complete Carb rebuild job he did 1 year ago. He said, Carb can still get gummed up with ethanol varnish, even after a short amount of time.

Explained to Marine Tech that I checked for Ignition Wire arching under the cover of darkness last night, and could not detect any arching from wires or Distributor Cap. He came right out and said 'It's not your wires, wires in a boat last forever' ! This seems very contradictory to what has been shared on this Forum. Then again, I'm not the Professional Marine Tech.
Honestly, the collections of knowledge and experience from members of this Forum, have been invalluable !

I find it extremely difficult to believe that the ethanol gas can be constantly causing my issues. Can't just be me ! Everyone would be having problems with their engines. Problem has to be something unrelated to gas.

Let me ask one last question..... If new Distributor Cap and Rotor, do not correct the problem, next replacement part may be the Coil.
Just a process of elimniation at this point....

How can you tell if you have a bad Coil? What are the symptoms?
Would symptoms be contant or intermitant, and it heats up?

Thanks agin.
Bigdog

[NoBozo]

Originally Posted by bigdog

Thanks MacShpMan for info about vent hose blockage. I have checked
hose at the top where it eixts the boat, however, have not checked
entire length of hose. Not sure how one would do that, or how to clean out.
Suppose I could run some plastic tubing down through the vent hose to check for obstructions, but then again don't want to force anything down
furhter if something is there....

I can relate to your friend's boat problems. I feel like I'm changing parts like clothes !

Talked to marine tech. this morning, he didn't have a chance to replace Distributor Cap or Rotor Friday because of backlog of customer repairs.
He's going to order parts Monday and work on boat Tuesday. After parts installed he said he'll take to nearby pond to test, best he can do under the conditions. I plan to be on that ride myself !

Marine Tech said it may be Carb problems again, but I reminded him the Carb about the complete Carb rebuild job he did 1 year ago. He said, Carb can still get gummed up with ethanol varnish, even after a short amount of time.

Explained to Marine Tech that I checked for Ignition Wire arching under the cover of darkness last night, and could not detect any arching from wires or Distributor Cap. He came right out and said 'It's not your wires, wires in a boat last forever' ! This seems very contradictory to what has been shared on this Forum. Then again, I'm not the Professional Marine Tech.
Honestly, the collections of knowledge and experience from members of this Forum, have been invalluable !

I find it extremely difficult to believe that the ethanol gas can be constantly causing my issues. Can't just be me ! Everyone would be having problems with their engines. Problem has to be something unrelated to gas.

Let me ask one last question..... If new Distributor Cap and Rotor, do not correct the problem, next replacement part may be the Coil.
Just a process of elimniation at this point....

How can you tell if you have a bad Coil? What are the symptoms?
Would symptoms be contant or intermitant, and it heats up?

Thanks agin.
Bigdog

Spark plug wires WILL deteriorate over time. Ten years of living inside that engine box with the heat will dry out the plug wire insulation and allow arcing...even if you cannot see it at night. Backfiring is likely an ignition problem. My educated guess is the distributer cap. Two screws loosened will allow it to be removed....without disconnecting the wires. Look inside the cap at the terminals around the inside rim. If the terminals look "Crusty", they can be scraped clean with a knife or screwdriver blade. The outside tip of the rotor can may also look crusty. Scrape them clean and you're back in business. Buy a new cap when you can scrape up the $45-50. I prefer Mercruiser parts rather than Sierra, even though Sierra is probably Half the cost.

Another possabity: If someone has been in the engine room, it's possable one of the spark plug wires came loose from a spark plug inadvertantly by being bumped into. I once actually had a spark plug wire dislodge itself from the plug during a backfire. At that time I was having plug wire crosstalking problems and at night, it looked like a christmas tree in the dark. If one leaky plug wire comes in contact with another leaky plug wire this will cause all manner of backfiring and rough running.

An ignition coil rarely fails, but when it does it usually happens when the coil gets hot and shorts out internally. When the coil is cold it may work fine.

BTW: A distributer cap for a boat with an inboard engine MUST BE Marine Certified. Automotive distributer caps are NOT acceptible.

[bigdog]

Thanks NoBozo for the info.

I have to agree with you about the Ignition wires ! I have replaced in the 3 yrs I've owned the boat, and don't know when previous owner replaced, or if wire are original?

The stalling and backfiring only starts after running boat for about 15minutes. When I initially start the boat it appears to run smooth, even under acceleration. Doesn't seem to be an issue.

If the Distributor Cap and/or Rotor had corrosion wouldn't the stalling, running rough and back-firing behavior begin as soon as the engine was started ? Cap & Rotor being replaced next week with new parts. Not going to bother attempting to clean, as parts may be original ?

Also, I've been reading that the fuel pump (electric MerCruiser in my case),
can have problems with an internal diaphragm, causing improper flow and pressure of gas to the Carb. Under these circumstances the Carb would run 'lean'. I have been told when Carb runs lean and can cause 'back-fire' !

So we still have several possible issues causing the problem.

Trying to take a one step approach, with the least costly first.
Will let Forum know results.

Oh...... I'll be on Winnie all next week, 8/8, with family and boat.
If I need to get additional parts over vacation, I have heard of M & M Salvage in Meredith. I realize all their parts are used.
Has anyone purchased from these folks ? Comments?

Thanks,
Bigdog

[macshpman]

If the vent is clear I would lean towards electrical. Coil could be the problem. I would lean more towards that then the cap, rotor, wires or sparkplugs. They would tend to act up all the time and not just now and then. I myself would change the pick up in the distributor first. Dont let the mechanic tell you that they are either good or bad. I personal have seen them work fine untill they get hot and then stop working. Once cold again it will work. I believe mercruiser has an update pickup because of this problem. Good luck

[dan]

Cold engine should be on full choke. Rich mixture. Engine warms up, choke opens, mixture leans out. Vac. leak somewhere causing lean backfire and or stalling?

[Jersey Joe]

Had the boat out last weekend for first time this year - I had replaced the coil, the fuel lines and the "anit-siphon valve". I ran for about 2 hours without stallling. I hope it is fixed, but last time out it took longer than that to exhibit the problem. Headed up to the big lake this weekend so I purchased Sea Tow insurance just in case and hope for the best.

[NoBozo]

There is one more thing relative to the distributor cap that I forgot to mention. Moisture. Moisture inside the cap will be evident by condensed droplets of water inside the cap when the engine is cold. The engine may run OK untill up to temperature, at which time the moisture wants to evaporate and turns into water vapor. Water vapor (fog) inside the cap is not conducive to smooth running. Perhaps if you have "hosed down" the engine recently, or got the distributer wet somehow, this might have introduced some moisture.

BTW: Looking for spark plug wires Arcing under the hood at night is always easiest to spot when it's foggy or hazy.....moisture.

My experience has been....the problem is almost Never as serious as it might seem. You are on the right track by looking at the least expensive solution because that is usually the correct one.

[bigdog]

Well tomorrow I should know if my engine stalling, backfiring problem has been resolved. with the latest replacements of Distributor Cap & Rotor.
(Hope marine techs thought to replace 'Pickup Wheel' in the Distributor?).
All to be installed tomorrow, then a in-water test with marine techs. At least that's the plan....

If this does not correct the stalling and backfiring, then I guess I have to look deeper to the root cause???

Again, the engine runs smoothly for about 10 minutes. After the engine stalls and backfires, I can almost always start up right away, and run at wake speed, but that's all..... As soon as I begin to increase throttle, stalls again.

After talking to a multitude of people about my engine problem, both here in this Forum and others friends, the following suggestions have been given as the possible issue. Came up with a list of 12 possible problems,
not necessarily in any particular order.

Gentlemen... Place your bets on your number !

1. Ignition module
2. Ignition wires - broken inside insulation and shorting out
3. Coil bad
4. Ignition Timing not set properly - Late timing
5. Electric fuel pump-faulty pressure loss
6. Water in fuel causing lean fuel condition
7. Carb Accelerator pump sticking
8, Choke open or sticking
9. Anti-syphon valve clogged
10. Firing order - Plugs not connected correctly to Distributor
11. Carb jets clogged
12. Bad Valve

[SIKSUKR]

I would definately look at the fuel tank vent.This has a sign of a fuel tank not being able to vent. I would rule that out by disconnecting the fuel vent line temporarily while running under similar conditions that you have already done.This is a test that costs nothing.If the valve has failed and wont let the tank vent,It's like sucking out of a bottle.

[ITD]

Originally Posted by SIKSUKR

I would definately look at the fuel tank vent.This has a sign of a fuel tank not being able to vent. I would rule that out by disconnecting the fuel vent line temporarily while running under similar conditions that you have already done.This is a test that costs nothing.If the valve has failed and wont let the tank vent,It's like sucking out of a bottle.

Easiest way to test for this problem is to crack open the gas cap when the boat starts stalling. If the boat restarts you've found the cause.

[LIforrelaxin]

Running a boat out of the water is not a good why to test how it is running especially if it a through hub exhaust..... by running it out of the water you take the back preasure of the engine exhaust system.... running on muffs is good if you are trying to start the boat for the first time in a while or, winterizing, and hey evening if you just but some new plugs in, but it is not a substition for running it in the water....

[6meter]

I have read this whole thread and sounds just like my fathers and my boat. Dads boat is gone so I can't check it but my solution was the coil. Run for a while then backfire with no power above idle. Would start right up if stalled.

[XCR-700]

Hummm, always interesting to see us amateur mechanics voicing our opinions, so let me not be stifled,,,

I’ll bet an extra thick frappe from Sawyers that its either the ignition coil or if it’s a Mercruiser then possibly the distributor module.

My argument would be that if its running good at any point its probably not any of the other items discussed.

Seems to me like a classic ignition coil problem, but having had those crappy Mercruiser distributer modules burn out, I wont rule that out.

That said, some of the checks suggested are easy enough to work through and eliminate. Re-checking the firing order, checking the condition of the plug wires, unscrewing the gas cap, and replacing the fuel with known/new good gas are all easy and sensible things to do and probably should try.

But I’m sticking to my prediction and I don’t give up my Sawyers coffee frappe without a fight, so I look forward to the outcome.

Best of luck.

[bigdog]

XYR-700 I'll take that bet ! Make it 2 Sawyer coffee frappes !

All below have been performed:
Checking the firing order, checking the condition of the plug wires, unscrewing the gas cap, and replacing the fuel with known/new, added Seafoam to gas.

Today marine techs repalcing Dist Cap & Rotor. Next sstep 'coil' replacement !

After that, not sure what I'll do next, but defintely will NOT bring boat back to currrent repair shop.

Stay tuned about progress....

Bigdog

[Jersey Joe]

3 reputable mechanics down here also suggested the Coil on my OMC, one of them also talked about the Vent (told me to open the gas cap as soon as the boat dies to see if there is suction) as well as the Anti Siphon valve. So, we replaced all, and threw in new Fuel Lines and a new filter/sep as well. So, hopefully we are fixed, but may never know what the fix was.

[bigdog]

Reporting back......

Just got off phone with marine techs, they replaced Dist Cap & Rotor and adjusted timing. They replaced plugs also, even after I told them not to do that, and that I had just put plugs in the engine ! What a bunch of clowns !
I've had it with these guys, and will never use them again !

BTW, They said the problem was defintely not the Coil !
He also checked the antisyphon tube. He stated it wasn't the Vent hose either.

They said they performed an in-water test, and the engine is showing the same behavior, stalling, sputtering and backfiring. The Tech checked the Carb and said the bowl is not filling up with gas. Tech said he couldn't do a pressure test on fuel pump side, that his test gauge only reads up to 5psi or something. Sounds like he doesn't know what he's talking about?
Long story short, he said engine is not getting the gas.

They now said the problem is the electric fuel pump, and want $250 to replace this part, not including labor ! RIGHT ! I wasn't born yesterday !
Not giving them another penny after this fiasco !

Going to drag boat to Winnie this w/e during vacation to try to diagnose and fix myself...

I may just fix boat with some plastic C4 ! Sorry venting !!!! Very frustrated what can I say.

Thanks for all your help and suggestions.
Bigdog

[EZ-Pass]

Sounds like you'll need to find another/new reparable dealer/marina.

[NoBozo]

Cash for Clunkers . Just kidding. BigDog..you have spent the rent on this problem. The BOAT is not the problem. Your Techs are taking advantage of you. Go back and look at the posts. Just about all the suggestions ...to solve the problem.... can be carried out by YOU....at almost no expense. This problem is NOT complicated. Unlike a computer.....It would be very difficult for you to Screw it Up....ie Do Damage to the engine or systems.

If this was a Computer you were fooling around with in the dark, ....(without a basic knowledge) ...I would say ...You have no choice: LET ..some OTHER/NEW experts look at it...BUT this is a SIMPLE internal combustion engine. THEY replaced everything...............OR DID They.

Take the boat home and look back over this years posts.

I will go back to your earlier numbered list and will eliminate some of the possibilities right off.

[NoBozo]

Originally Posted by bigdog

Well tomorrow I should know if my engine stalling, backfiring problem has been resolved. with the latest replacements of Distributor Cap & Rotor.
(Hope marine techs thought to replace 'Pickup Wheel' in the Distributor?).
All to be installed tomorrow, then a in-water test with marine techs. At least that's the plan....

If this does not correct the stalling and backfiring, then I guess I have to look deeper to the root cause???

Again, the engine runs smoothly for about 10 minutes. After the engine stalls and backfires, I can almost always start up right away, and run at wake speed, but that's all..... As soon as I begin to increase throttle, stalls again.

After talking to a multitude of people about my engine problem, both here in this Forum and others friends, the following suggestions have been given as the possible issue. Came up with a list of 12 possible problems,
not necessarily in any particular order.

Gentlemen... Place your bets on your number !

1. Ignition module
2. Ignition wires - broken inside insulation and shorting out
3. Coil bad
4. Ignition Timing not set properly - Late timing
5. Electric fuel pump-faulty pressure loss
6. Water in fuel causing lean fuel condition
7. Carb Accelerator pump sticking
8, Choke open or sticking
9. Anti-syphon valve clogged
10. Firing order - Plugs not connected correctly to Distributor
11. Carb jets clogged
12. Bad Valve

------------------------------------------------------------------
1. Ignition module.....??

2. Ignition wires - broken inside insulation and shorting out. Spark Plug Wires?? They are now new...YES?

3. Coil bad. MAYBE

4. Ignition Timing not set properly - Late timing. Timing does NOT CHANGE by itself. Timing once set is good for the life of the engine. Period. The timing is adjusted by "twisting" the distributer one way or the other and then tightening it back up. CHECK IT: Grab a hold of the distributer with both hands and try to twist it. IF it turns..then your timing is OFF because the clamp down screw is loose. If it's loose..come back here and ask how to fix it.

5. Electric fuel pump-faulty pressure loss. DO You KNOW that you HAVE an Electric fuel pump..??..or did someone just TELL you..?? My 5.7 Mercruiser V8 (1986) has a mechanical pump.

6. Water in fuel causing lean fuel condition. Water does NOT LEAN the mixture. It will just "WET" the spark plugs and stop the engine.

7. Carb Accelerator pump sticking. This only comes in to play when you GAS IT....pedal to the metal...

8, Choke open or sticking. Choke is supposed to be open when the engine is warm. It's automatic. Take off the "flame arrester" (looks like an air filter) and look at the choke..when it's COLD, .......and after it warm. It looks like a little door that is shut when cold. Good. When it warms up..the little door should be fully open. GOOD.

9. Anti-syphon valve clogged. In all my years (I'm 67) working on engines: I have NO IDEA what an Anti Syphon Valve is.

10. Firing order - Plugs not connected correctly to Distributor. If the engine runs at all.....this is unlikely. If Two plugs are miswired..switched..the engine will NEVER run smoothly.

11. Carb jets clogged. This IS Possable..ETHONAL.

12. Bad Valve. What valve? NOT Likely

BIGDOG: Cheer up..You are getting close to the solution.

[Jersey Joe]

Nobozo

I did not know about the Anti-Siphon valve either, until a mechanic told me to check it.

Apparently, what it does is prevents the tank from emptying inside your hull if you should develop a leak (at least what he told me). It is a 1 - way valve from the tank to the vent. If fuel runs out of the tank too fast, the valve will close and create a vacum in the tank. Mine was all crudded up with an off white crusty buildup, probably from ethanol.

The Mechanic I was working with told me that this would make sense for my problem - because the boat will run fine at idle, but when you push the throttle down, once you burn off the fuel in the carb, you can't pump enough fuel back into the carb to keep it running above an idle becuase the valve creates a vacum lock in the tank. In my instance, if you let the boat sit for a half hour - it will run fine again - which would make sense as air gets back into the tank to break the vacum.

I am no expert - just adding what limited knowledge I have to help a fellow boater.

Hey BigDog - I carry a wrench that fits my drainplug on the boat at all times, much easier and quieter than the C-4

[6meter]

Nobozo, I would say that you're right on. But I'll add a thought on a couple of things on the list. The firing order should be right, the problem was there before the plugs were changed. Will the ethanhol eat the diaphram in a mechanical fuel pump? I believe Bigdog's boat is a '96 so it could have an electric fuel pump. I borrowed my brothers coil to try 2 years ago. It fixed it. Ran great last year. Dies out this year. So there is interest in this topic for me. I'll admit the same about an anti siphon valve. Did they use them in '86? A distributor module will act just like running out of gas. Will stay tuned.

[NoBozo]

Originally Posted by Jersey Joe

Nobozo

I did not know about the Anti-Siphon valve either, until a mechanic told me to check it.

Apparently, what it does is prevents the tank from emptying inside your hull if you should develop a leak (at least what he told me). It is a 1 - way valve from the tank to the vent. If fuel runs out of the tank too fast, the valve will close and create a vacum in the tank. Mine was all crudded up with an off white crusty buildup, probably from ethanol.

The Mechanic I was working with told me that this would make sense for my problem - because the boat will run fine at idle, but when you push the throttle down, once you burn off the fuel in the carb, you can't pump enough fuel back into the carb to keep it running above an idle becuase the valve creates a vacum lock in the tank. In my instance, if you let the boat sit for a half hour - it will run fine again - which would make sense as air gets back into the tank to break the vacum.

I am no expert - just adding what limited knowledge I have to help a fellow boater.

Hey BigDog - I carry a wrench that fits my drainplug on the boat at all times, much easier and quieter than the C-4

------------------------------------------------------------
Thanks Joe for your response. It got me to thinking and got me off my butt to do some Googling and here is what I found that makes sense to me:

Question: My fuel tank is higher than my engine. Do I need an anti-siphon valve? There is a small round valve installed just above the tank where the fuel line leaves the tank. Could this be some sort of anti-siphon valve?

Answer: The valve to which you are referring is probably a small spring-loaded one-way check valve. The spring-loading on the valve is sufficient to prevent fuel from passing through it statically through a siphon (usually no more than 2 or 3 psi), but low enough so that the fuel pump can pull fuel through its mechanism while the engine is running.

These check valves will sometimes create a problem with electric pumps, since they (electric pumps) are less forgiving of even slight increases in suction head than are mechanical pumps.

If there is a wire connected to the valve on your boat, it is probably an electric solenoid valve that spring-loads closed whenever the ignition switch is turned off, and power is removed from the valve. These valves have the advantage of adding virtually no head loss to the suction side of the fuel pump, but they are vulnerable to malfunction, since they rely on electrical energy to hold them open.

It is not at all clear to us that either of these valves is actually required by the Coast Guard. In our experience, most people rely on a manual valve to prevent fuel from passing from their fuel tanks when the boat is left unattended. - Updated: January 5, 2004
-------------------------------------------------------
My take (NB): In Short; This valve is a TWO STAGE valve allowing gas to be Sucked through it by the fuel pump, but will NOT allow fuel to "Siphon" out "on it's own".

Thanks again Joe for a teachable moment. I learn something new every day.

[bigdog]

Jersey Joe,
Your explanation describes my engine symptoms exactly ! However the marine tech said he checked the A.S.V today and it appears to be working as it should and is not obstructed. I did not examine myslef, so I cannot confirm.

Also love your comment and humor about keeping a wrench that fits my drainplug, rather than my C-4 alternative ! What can I say, I like things that go BANG !


NoBozo,
Your discertation about the A.S.V. was very accurately described perfectly !
Thanks for educating the rest of us who may not understand how this part functions.

[bigdog]

Well… here’s the most recent update….

At the advice of my Marine mechanics, they replaced my Distributor Cap, Rotor, and checked the ignition Timing. BTW, the Cap & Rotor looked almost ‘new’, with no signs of corrosions whatsoever. Timing was right on !

Mechanic said he removed Anti-Siphon Valve and inspected and that it looked good, and ball inside was not sticking. I guess I have to believe him, but who know if he wasn’t just giving me lip service? I did look at the ASV fitting and it may have been removed.

They took the boat to a small lake nearby the shop to give it a in-water test. Within a short amount of time as they gave full throttle, the engine began to cough, backfire and finally stall. There they were these 2 guys in the middle of the lake with the boat stalled. I wished I could have seen the look on their faces ! HA !

After stalling, one mechanic checked the Carb bowl and it was totally empty of gas. After a few minutes, they were able to restart the boat, and noticed that the Carb bowl refilled with gas. They ran at below wake speed and made it back to the ramp.

They are now convinced that the problem is related to the ‘electric fuel pump’. And for another $350, would order the part, install, and I’d be in business. Not wanting these two geniuses to work on my boat another minute, I picked up the boat and brought home this morning. I’m out more money for unnecessary repairs, and a boat which is still not working, and just before vacation !

I now do believe the problem could be in fact fuel related, whether it is the ‘electric fuel pump’ or not remains to be seen. The only way to determine if the fuel pump is defective would be to perform a pressure check. Apparently, the mechanics could not do a pressure test because their pressure gauge they have starts reading at 5lbs. I believe the electric fuel pump pressure puts out between 3-5lbs. So short of buying and installing a new fuel pump to test this theory, I will have to wait to take to a marine shop which can perform this test with the correct equipment.

Saturday morning I begin my 1 wk vacation in Meredith, can’t wait ! I will be towing my boat up to the lake for the week, and hopefully diagnose during this time. One way or another, I will be using my boat this vacation, even if it means sitting in my boat, anchored just off-shore ! Wave on your way by !

Thanks for everyone’s feedback. This has been a great Forum Thread and provided me a wealth of information. I know a lot more now than when I began this quest. Lessons learned !

Bigdog

[SIKSUKR]

Oh BD I feel for you.I also know that somehow you will get this resolved for or during your vaca.Keep your chin up.It sounds like your on the right track with the fuel issue.

[XCR-700]

So sorry, sounds like you have been the victim of lousy mechanics and an unethical business.

I can only tell you what I would do from this point.

First, buy the coil, its very inexpensive and easy to install and will eliminate it from your list.

Next, run the boat with the gas cap off, that way there is no question about the vent, or valve, or anything on that end.

If it still doesn’t run, disconnect the fuel line from the main tank and plug it, and then get your hands on a portable tank, again its cheap and will flat out eliminate any concern about kinked lines, blocked pickups, or anything to do with the tank.

At this point its either going to run or your going to know your down to fuel pump, or distributor module and/or ignition module.

So if your still chasing it, you will again need to run it until it stops and determine if its actually “running dry” or loosing ignition.

The “running dry” theory should very easy to determine, add a simple fuel pressure gauge before the carb, you will know immediately if there is no fuel pressure, you have a bad pump.

If there is pressure, then I’m going to rule out the carb as if it ever runs well, but only acts up when hot, you probably back to an ignition problem, so if it’s a Mercruiser, I would pop for distributor module, I’ve had several die on me and its my understanding that its one of the most commonly sold parts.

My money (sorry - frappe) is still on the coil, but I reserve the right to switch to the distributor module at any time,,,

Make a plan, keep it simple, don’t go looking for things that are not likely problems before eliminating the ones that are likely, and stick to the plan and you will get it resolved.

Keep us posted.

[VitaBene]

I hope you have a great vacation week boating!

[bigdog]

Just to provide this Forum THread with some more feedback...

Today I pulled the fuel vent host off the gas tank. I was able blow through that end of hose Volumes of air, which came out the back ot the boat.

No visible signs of obstruction, or any debris came out of the hose.
This eleimiates this as the problem.

The list is getting shoter...
If it's fuel related which I suspect, because the Carb bowl is dry after stalling,
the problem can only be the 'Electric fuel pump'. The Anti-Siphon valve was checked and was toi be found OK. Not sure what else it could be if fuel related?

Don't see how an ignition probllem could cause the lack of fuel to the Carb?

Well, any further diagnosis will have to wait until I arrive in Meredith this w/e.

[Airwaves]

You may have posted this already, but Where did you take your boat for repair????

The basics you have covered, Fuel, oxygen and spark.

Reading your post it is fuel starved. Why? Good question.

Before I'd spend much more money try this if you can. Attach another fuel source to your engine (portable) and see what happens.

I don't know if that's practicle on not but if you do it and it runs great then it might be your fuel pump? If it still does the same thing then the fuel pump probably isn't the answer.

Good luck and let us know.

[ApS]

Originally Posted by bigdog

"...The list is getting shorter..."

It really is, and I applaud your efforts to "DIY".

I haven't read where you've changed the fuel line from the pump to the carburetor. I've had even a braided stainless steel brake line "squish itself shut"! (And a brake pedal's pressure is some pressure to overcome. )

Electric fuel pumps in the range of 3-5 psi can be tested by using your thumb to halt its pressure. They should also put out enough pressure to squirt gas strongly as you release your thumb. At only 3-5 psi, I'd expect a simple gravity-feed from an alternative tank would run your engine—even under a load.

The diaphragm inside can develop a leak. It may be a relatively easy fix, and a kit may be available from NAPA stores. You could even make a decent diaphragm by cutting one out of a suitable material, like material from a "close-enough" repair kit. How's that for "DIY"?

Originally Posted by bigdog

"...One way or another, I will be using my boat this vacation, even if it means sitting in my boat..." )

Hey, I believe we have the makings of a "lake sailor" here!

[CL 240 LS]

Hi Bigdog
I reread the thread on gas tank, http://www.winnipesaukee.com/forums/...ead.php?t=7494

You said you drained most of the gas but the bottom 5 gallons remained. Are you sure there is no debris in there? Did you located and check the pickup tube and was there a screen on it? Maybe worth looking at again no matter how big of a pain.

[bigdog]

Hi again....

I will respond to each of the recent Posts in order:

Airwaves
Alternative fuel source test, have not done yet. May be the next test I'll perform this w/e when I arrive in Meredith for vacation. Certainly would prove
conclusively if this is fuel related, and rule out ignition issue.


Acres per Second
Have not changed the fuel line. The diaphram in the fuel pump cannot be repaired, it is a sealed unit. I think they make it that way so you have to buy new !

CL 240 LS
I personally did not check the pickup tube, but my marine tech, recently removed checked the Anti-Siphon valve, which he said was working perfectly fine, and the ball inside ASV was moving freely in the fitting as it should.
BTW, what is 'CL 240 LS' a Crownline ? If so you're one lucky guy !

[CL 240 LS]

That I am!

Hope you get up and running soon. Try finding a portable tank and hooking it up to eliminate as much of the fuel line components as possible. Maybe a local marina has such a setup that they can try?

[Jersey Joe]

OK, I have to share this with you folks, because it is almost unbelievable.

First off, I "think" "hope" that my stalling problem is fixed. We went to fireworks in Alton Bay Saturday Night, went to Weirs Beach Sunday, and went to Center Harbor, and then to Meredith for Dinner Yesterday, without a problem ! ! So, bigdog, assuming I am fixed, it was the ASV, Coil, Fuel Line from Tank to Engine, or Vent Line.

Now for the story....

When going to fuel up yesterday, I want to pour my StarTron into the tank. Did not realize the the little Plastic/Paper Seal thing under the cap was stuck on the top of the bottle. As I tipped the bottle to pour it into the tank, you guessed it, the little disc went happily into the fill hole!!! What are the chances ? So, I went over (I was at West Alton Marina) to the mechanic and talked with him. He told me, you have to get it out because it could plug up your intake and ....make the boat stall..... So, we have an appointment tomorrow morning and he is going to try to fish it out of the tank through the sending unit acccess hole.

Just wanted to share what I hope is the fix, and the simply unbelievable story.

JJ

PS - Good

[Fishy Cover]

I had the same problem with a Mercruiser 3.7. After a mechanic changed the points, rotor, condenser and coil it ran in the driveway (with earmuffs) but stalled out when I accelerated on the lake. Next I changed the fuel filter and dumped the contents into a clear container and it was 90% water. So I drained the tank thru the hose attached to the fuel pick-up and there was some water but not as much as I expected. I also found that the hose from the fuel pump to the fuel filter had a kink in it that may have restricted fuel flow so I replaced it. I know that there could be a small amount of water in the bottom of the tank that the pick-up did not reach so I poured in two bottles of drygas and 1 bottle of Seafoam and then added 10 gals of fresh gas.

It started in 2 seconds and ran well on the lake at varying speeds from idle to 4000 RPM for the first hour and then I took a prospective buyer out for a second hour: still no problems. Hurray!

The buyer trailered it to his lake last Sunday and added about 15 gals of fresh gas along the way.

The buyer called me on Monday to tell me that he had been out for about 3 hours the engine ran well but he was now in the middle of his lake and the engine had stalled and would not start.

Although it was an as-is sale I feel badly about it. It does not seem that he would be out of gas-- combined we put in 25 gals and ran the boat 2 hrs here and 3 hrs there. Is this engine that thirsty?

If anyone has any suggestions they would be greatly appreciated.

[EZ-Pass]

It is starting to sound as if you had better join the famous clunker reward program with a boat.

[LIforrelaxin]

Big Dog,

As it is appearent you have been having the work done to your boat.... may I suggest Goodhue Marine in Moultonboro.... I have been using Brett and the boys for several years..... If you are having an issue with fuel getting to the carborator they will figure out why.....

[6meter]

OK Bigdog, what are the results? Did it run all week? What did you replace?

[EZ-Pass]

Originally Posted by 6meter

OK Bigdog, what are the results? Did it run all week? What did you replace?

It's been almost 2 weeks since Bigdog gave us any input. Maybe the boat is up on a trailer for the rest of the season.

[Rubberguy]

The presence of ethanol in gas has caused some interesting problems, especially for older carburetors. Because ethanol is a polar molecule, it reacts with the rubber components (usually Nitrile rubber) and causes it to swell abnormally. There is a new sta-bil that is being offered specifically for ethanol containing marine engines. It's fairly expensive, but places like Dave's Motorboat Shoppe offer it.

[NoBozo]

Originally Posted by Rubberguy

The presence of ethanol in gas has caused some interesting problems, especially for older carburetors. Because ethanol is a polar molecule, it reacts with the rubber components (usually Nitrile rubber) and causes it to swell abnormally. There is a new sta-bil that is being offered specifically for ethanol containing marine engines. It's fairly expensive, but places like Dave's Motorboat Shoppe offer it.

Hi Rubberguy. What type of material would be a Good or Best replacement for Nitrile rubber in an ethanol environement? Just wondering. NB

[Wolfeboro_Baja]

Originally Posted by Rubberguy

The presence of ethanol in gas has caused some interesting problems, especially for older carburetors. Because ethanol is a polar molecule, it reacts with the rubber components (usually Nitrile rubber) and causes it to swell abnormally. There is a new sta-bil that is being offered specifically for ethanol containing marine engines. It's fairly expensive, but places like Dave's Motorboat Shoppe offer it.

I have also seen Marine Stabile (blue in color, not to be confused with the red formula) sold at VIP Auto Parts stores and AutoZone stores.

[bigdog]

Hello everyone !

Back from vacation, had a great week 8/7-8/15 in Meredith. Luckily that was a fairly good weather week. We didn't use the bowrider that week,
beccuase it was still not repaired. That was a big disappointment for the family. I did bring my 3 kyacks on vacation, so the family could at least have a little fun on the water. Still not the same

Long story..... after another inspection of stalling problem by a professional marine mechanic in the Lakes region, it was determined that the problem
(lack of fuel to Carb), is being caused by the 'electric' fuel pump ! *@^&@*#&(@!&^%$&@%#&@!^#

The internal diaphram inside the pump has most likely failed or deteriotated.
This could be a result of age or ethanol or both ? I believe there is also a metal ball inside the pump which can also stick, stopping flow of fuel.

They do not make a 'rebuild' kit for this electric pump. A new fuel pump was ordered and I received today. I plan to install over the weekend and test boat/engine on the water, weather permitting.

Will report back to Forum with results. Keeping my finger crossed !

Bigdog

[bigdog]

Reporting back, with SOME progress...

Yesterday was a wash out literally around here in Central Mass. Rained cats & dogs most of day.

Today, Sunday, I was able to get to remove old electric fuel pump, and replace with new one. Actually came out rather easily ! Installed new pump, and boat started almost immediately. Actually, quicker than it ever has before? Maybe just a coincidence? Sure ! Engine ran smoothly, shut engine down after running 10 min on motor-muffs, without any incident.

Did not have time today to test run on the water. Hopefully, tomorrow or Tue, I'll have that opportunity.

I did notice, that the old pump, was not original OEM, or have Mercruiser part number stamped anywhere ? Pump must have been replaced in the past sometime, just guessing..... Pump looked like some generic, not OEM or Sierrra?

Also, I also noticed one end of electric pump had a small screen inside, but appeared to be covered with what looked like 'black gunk' like material like molassess! Ethanol residue maybe? Cannot open the pump to look inside because it is a sealed unit.

I also tried to perform a test to see if I could blow air through one end of pump, and come out other end. I could pass some air through, but seemed very restricted, maybe blocked. I tried same procedure on new pump before installing and was able to force more volume of air through the pump cylinder. Maybe it was just me, but the air flow through new pump seemed to allow more volume through?

Just FMI,when the electric furl pump is working, is it suppose to emit and sound or noise. My pump appears to work completely siltent. I am assuming this is normal ? FORUM Thoughts?

Hopefully, the electric pump was the problem, the water test will be the ultimate test to prove this theory.

More to come!

[chipj29]

I think you found your problem. It is possible that the fuel pump was operating, but just not able to get enough fuel due to the blockage you found in the screen. This is exactly what ethanol has done. In some cases, it breaks down the fuel tank or even the fuel lines, and the residue clogs carb jets or fuel pump screens. It is actually very common.
Do you have a 5 gallon portable gas tank that you have used for a number of years to fill up your lawn mower? If so, when it is almost empty, take a look in the bottom of the tank and you will see that brown gunk that you are talking about.

[robmac]

Congrats Kevin sounds like you've got it,hope the in water test is the same. New pump technology keeps them pretty quiet and when they start getting noisy that's your first indication it on its way out. Just ask a Chevy or GMC truck owner.

[NoBozo]

Electric fuel pumps usually make a Clicking noise when you first turn the ignition key on....until the pressure builds up and then the clicking will be much less noticeable. If you start to run out of gas in the tank, the pump will start clicking vigorously.....because it is pumping AIR. NB

[bigdog]

NoBozo... Not hearing ANY clicking sound either during initial startup of engine or after ruuning awhile.

I have to ASSUME it's working ok, otherwise no fuel would be pumped to the Carb, and engine wouldn't be running.....

Make sense?

[NoBozo]

Originally Posted by bigdog

NoBozo... Not hearing ANY clicking sound either during initial startup of engine or after ruuning awhile.

I have to ASSUME it's working ok, otherwise no fuel would be pumped to the Carb, and engine wouldn't be running.....

Make sense?

YES! It's maybe a different design than I'm familiar with. I'm still wondering how any "Gunk" got into the old fuel pump. The Main fuel filter should have protected it. I would think the best arrangement would be to have the Main filter between the tank ....and pump/carb so the filter can protect the pump as well as the carb.

Glad to hear it's finally running. Time to start using "Star-Tron". ....and keep a Spare Main fuel filter in the boat because the "Gunk" will probably keep coming for awhile.

BTW: The Main fuel filter is AS Big as an Oil filter and also removes any water than comes from the tank. You can remove the filter and Shake any water out of it but the "Gunk" will STAY in the filter. NB

[wq081103]

Originally Posted by bigdog

Hi Folks,

Have a engine stalling problem which just can't seem to be resolved?

Problem is engine runs fine 'in the yard' with 'muffs' attached. I've run for more than 30 min. even up to 2500RPM without issues.

However,when I run boat in the water, it coughs, sputtters and stalls just about immediately, attempting to go more than wake-speed. Doesn't seem to run under a 'load', but appears to run fine idleing in the yard
'on the motor-muffs'.

I am using ethanol gas, which still has Sta-Bil and ValviTech treatment from
last season. I checked samples of gas, and all looks ok, doesn't look like any water in gas. Gas looks clear, no bubbles, or any type of foreign particles. The fuel/water separating filter has been changed-out twice. I changed spark plugs. Dealer has performed a coplete Carb rebuild. No difference in engine behavior? Dealer still thinks there's some water in the system. They have ruled out this being 'fuel pump related.

OK, if there still s some water in the gas it doesn't seem prevalent or obvious? I have 35 gal of gas in the tank now. If I have to drain it out and start with fresh, any siuggestions how I would go about doing this?
I'd have to have 7-8 five-gal cans, which is inpractical. Secondly, what am I suppose to do with this gas once drained? Dealer has not been very much help, and is not setup to handle this situation.

Would appreciate any suggestions about the gas question, or maybe comments about the engine behavior not being gas related.

At 'wits end' !!

I have run into similar problems with auto's. If you suspect water in the fuel ..try mixing 91% Isopropyl Alcohol (dry gas) wich can be purchased at any cvs... etc. The alcohol will mix with the water and allow it to be burned in the fuel system. You will more than likely want at least a quart+/- depending on the amount of water present and the quanity of fuel in the tank. Also check the ignition wires (if applicable)or coil packs. excessive resistance (ohms) or internal breaks can also cause this situation under a load. Silicone based sprays like "Wire Dryer" is a diag. tool to be used on the ign. System, if moisture is present on the components it will also create your trouble. I hope this will help you on your repair.

[bigdog]

Finally reporting back.....

Have not had a chance to report back, too many other non-related other priority issues geting in the way of boating.... Work & Family obligations !

Anyway, got the new 'electric' fuel pump installed. Was actally and easy replacement for a DIY Ran engine in yard on motor muffs for about 15 min w/o any issues. But then again, it ran fine on 'muff's', with old fuel pump.

Took the boat to a small lake nearby with my grandson for first test run after new fuel pump installation. Got a late start on water about 3:00pm, and weather was a lot cooler here in Central Mass on Sun about 70 deg, with a light wind. Certainly not like the warm and toastie Sat 82+

We ran the boat around the lake for a while, w/o any hesitation, coughing or stalling. I was just waiting for symptoms to appear , but nothing seemed to happen? Got boat up on plane from a stopped position several times, w/o any problems. Really put it under a 'load', seemed to run fine... WIth old pupm, I defintely would have noticed symptoms immediately under this test.

Only ran boat for about 30 min, stopped, dropped the anchor, had lunch, went for a swim (the water was still very warm), then headed back to boat ramp. By that time it was already 5:30pm, getting a lot cooler, and sun was
starting to drop.

Again, no problems ! I can't say 100% that probem has been solved, because I really didn't have a chance to run the engine on the water as long as I wanted to, wish I could have tested for an hour or so..... Everythingl considered though, all seemed fine. This being said, all things definitley point to a bad 'electric fuel pump' ! Unfortauanltely, spent a ot of $$$ in between, partly as a result of 2 bonehead marine techs ! Lessons learned, do my own research and analysis first !

I may take boat out again before winterizing for season ? Depends on schedule and available time... TBD?

FYI, even though boat seem to be working now, I am planning to move up to a larger, newer boat (2004-2008), next season if budget allows.

Thanks everyone for all you help, information and encouragement, much appreciated !

Bigdog

[jst_4_kiks]

great news to hear bigdog. glad you got it figured out and now are happily boating with no issues.

[Shirneen]

FINALLY, after 3 years of our Four Winns 3.0 Cobra engine stalling out every day after running for 30 minutes or so, the problem has been solved. In the last 3 years we have done everything: New spark plugs and wires, new distributor cap and wires, carburetor cleaned etc, new thermostat, on and on. Today the mechanic went back and was going to replace the carburetor and discovered that the gas line going into the carb. was almost totally blocked with black "gunk". With that cleaned out, the boat is purring like a kitten and running perfect. Hasn't sounded this good in years and since everything else is new, I have high hopes for the rest of the summer and the grandkids are arriving this week. Perfect timing!! Just suck it up and pay extra for the gas with no ethanol. About $5 a gallon if you can find it!! Good luck.

[Descant]

Where do you get non-ethanol fuel?

[VitaBene]

Short of aviation gas, I don't know anywhere around the lake that stills sells ethanol free. Most marine suppliers add startron or similar.

[Dave R]

Originally Posted by VitaBene

Short of aviation gas, I don't know anywhere around the lake that stills sells ethanol free. Most marine suppliers add startron or similar.

There's a gas station near the Maine/NH state line on Route 25 in Freedom (22 miles from Wolfeboro) that sells 89 octane ethanol-free gas for $4.29 a gallon. I bought 5 gallons for my BSA motorcycle (fiberglass tank) on Sunday morning.