Water Pump Impeller Replacement
 

Just started the boat and water pump squeeled at me.

Need an impeller replaced ASAP

Any suggestions in southern part of lake?

Thanks

They usually only do that when they are dry. If it's clogged with something it will make the belt slip and squeel. Any chance of either of those possibilities?

Assuming what Dave R mention doesn't work replacing the impeller would probably more expensive and also finding the part than to buy a new pump. Parafunalia or a marina store(Irving) should be able to help you out.

Dave M

How do you know it was water pump and not a loose belt? Did you run the boat on the muffs? Do you have water flowing out the exhaust?

Changing the impeller yourself is doable.... but how easy it is depends on what you have for a drive setup....

Volvo Penta - usually mounted on the crank pulley and very easy to change

Mercruiser Alpha - located in the drive. You need to split the drive in two. Easy but can be time consuming...

Mercruiser Bravo... located on the motor lower left side (when facing the motor) Its a pain to replace... mostly because you have to practically hang upside down to disconnect the pump to get to the impeller...

Or.. just call around to the local marinas to see if they can fit you in... although my guess is they "might" get to it sometime next week

Woodsy

Dave Motor Boat in Guilford did mine last last year. He is an honest guy that will do it the right way.

Hmm just so you know the impeller and water pump are two separate items although both circulate water to (impeller) or through (water pump) the engine.

Squealing could be caused by anything usually belts squeal if warn, glazed or not properly tensioned, sure you don't have an idler bearing that is going, maybe the bearings in the alternator or PS pump (these squeal and moan really bad if low on fluid).

Yes a water pump can make noise but usually if the bushings or bearings go bad there is evidence of a leak around the shaft and noise combined.

I've never heard an impeller squeal and furthermore if you start the engine and run it for as little as a few minutes dry you'll destroy the impeller as it is just a flexible rubber vane in a stainless steel housing. It needs water to lubricate itself, lack of water will destroy the rubber.

I'd do a little more troubleshooting before you start throwing parts at it.

Issue resolved
 

Impeller was toast, changed it out.
Boat in water, all in fine in the world!!!🤗

Yay!

Did you do it yourself?

What power package is it?

So...

My participation in this thread seems to have jinxed me!

Three days ago I heard an unusual screach from my Mercruiser I/O (350 Mag with a Bravo Three drive) on start up.

A look in the engine compartment revealed no anomolies and evrything ran great...until today.

After about five minutes of running there was a horrofic screach and I lost my power steering.

Looking at the engine I could see that the serpentine belt was no longer moving.

I shut it down to investigate the cause.

The belt was intact but had no tension because the seawater pump pully had moved forward about two inches.

Sea Tow came and helped us get back to the mooring.

Irwin is all backed up and I believe the boat will need to be hauled to replace the pump unless the drive intakes can be temporarily plugged.

Who do you suggest I call?

Sorry I jinxed you, I’m a DIY and car guy, with some mechanical skills
Motor was an 8.1 merc, where water pump is low but accessible.

I have seen the waterpump pulled while in the water, he just plugged the water hose with a dowel. Call one of the mobile marine mechanics and see if they can help you out.

Or buy yourself a replacement water pump and tackle it yourself. Not that hard if you’re handy

Good luck

I did my 7.4 Bravo III at my dock. When you pull the raw water intake hose off it will flood the boat if left un-plugged. I forget exactly what I did but remember it wasn't a big deal.

I am wondering if I cam keep the water out by covering the intake holes on the drive.

If I plugged the hose hole on rectangular “ear muffs” and squeazed them tightly onto the drive, would it keep the water out?

The water outlet is in the transom assembly but that is after the exhaust elbows which are above the water line.

The job looks pretty simple but the space constraints of the engine compartment will make it a slow process.

I’d be happy paying a pro if they could do it soon.

The loss of prime boating season days has me considering doing the work myself.

That should slow it down enough to easily allow the bilge pump to keep up if it does not stop it fully. Put a plastic shopping bag over the inlet holes first and it will be even more effective.

The key to getting the pump out easily is to use a 1/4" drive ratchet. It will fit nicely behind the pulley. Some folks find it easier to remove the pump by taking the pump bracket off the engine first. If you can't get the hoses off with the pump in place, take them off after you unbolt the pump from the engine.

Thanks for the tips.

I'll call Mercruiser Monday morning to see if they have a complete kit for this. Their parts site shows only the individual parts.

I may consider aftermarket.

Has anyone here had any experience with going non oem for this?

All the major marinas will have the parts you need in stock. Just have your serial number when you call or go in.

The merc part number for the rebuild kit is 46-807151a14, though it may have been superceded. Bravo pumps have not changed since 1988 or so, so it should not be hard to find a kit. Aftermarket is fine.

If the old impeller is broken into pieces, you'll need to back-flush the system from where the raw water enters the thermostat housing, back through the oil cooler, fuel cooler (if applicable), and power steering cooler, to the pump outlet. The pieces usually get trapped in the power steering cooler and can cause enough restriction to make your engine overheat at speed.

Well that was fun...

I got a late start because my daughter's car quit and stranded her today.

New Rule: Only one broken machine at a time!

The pump is out of the boat and I did more stretching exercise today than I thought possible. I suspect my motion tomorrow will have a sound track of groans.

What started all this is the pully shaft and a bearing migrated out of the pump housing. The pully looks fine but will have to be removed from the shaft with, you guessed it, a puller.

I suppose it will then need to be pressed onto the new shaft of a new housing.

Hopefully the Mercruiser help line can steer me in the right direction on this.

The two hoses, red on top and black on the bottom, were not very long and as a result reaching their clamps was challenging. Reassembly will likely be much worse.

It looks like the impeller is undamaged so I won't need to go on a cooling system scavenger hunt for bits and pieces.

I hope to have this wrapped up this week.

Good luck! I know full well about paying in pain for attempting to accomplish impossible tasks!

I tell myself "Humans do this. I am a human, therefore I can do this."

Of course, training, experience and the lack of special tools often get in the way.

One thing is certain, I will learn from the experience.

Sounds like the rebuild kit I recommended will be of no use to you, it replaces all the parts that are still good on your pump. Sad to say, you will need the more expensive parts of the pump that should have lasted much longer...

If you would like to try and rebuild the shaft, pulley and bearing part (the "nose housing") of your pump, I'd love to give it a go, just for the experience, I've never done one of those. I have all kinds of tools for this kind of work in my garage here in Raymond.

Update:

It's raining and 53° so the installation will have to wait until tomorrow.

I now have in my possession a complete new pump.

I "borrowed" a pulley puller kit from AutoZone. Their program allows you to buy the tool with the expectation of returning it for a full refund.

The puller worked well so the pulley is off the old shaft.

I expect it to be easier to install the pump first and then add the pulley. A practice installation with the pulley tool showed me it will be easy to do.

Mercruiser telephone support gave me some tips:

A touch of motor oil on the pulley shaft.
Dish washing soap will aid in hose installation.
Some torque specs.
The new pump assembly is better because it has a circlip to retain the shaft in the housing.

My flushing earmuff flood abatement was adequate for removing the pump but I will augment that with the trash bag technique suggested here (thanks).

If any of you up in Wolfboro hear a tirade of cussing tomorrow it will be me down here in Paugus Bay applying some "verbal lubrication" to the task. :D

Whatcha gonna do with the old pump?

Sell it to you for big bucks! :D

Not familiar with this "buying something for big bucks" concept. Goes against ever fiber of my being... Seriously though, if you want, I'd love to take a look at it and see how hard it would be to fix. I live for stuff like this.

There's a Mercruiser 454 with new head gaskets, valve seals and recently lapped valves in my garage right now that I'm working on for/with a friend for fun. Should be dropping it back in his boat this weekend.

My best find ever (so far): I recently bought a complete 2005ish Bravo 3 lower gear case with only 22 hours on it, for 25 bucks (these are $3400 new). Has some minor corrosion, but is in perfect working order. I did not rip the seller off, I made sure he was aware that it was a ridiculously good deal; he had sold his boat, was moving to TN, and just wanted it gone but not wasted. I was simply looking to re-stock my spare parts bin after changing an outer prop shaft, bearing carrier, and seal, on my boat's Bravo 3.

The pump is in and everything is buttoned up.

Water PSI and temp are good, serpentine belt is running smoothly.

Thanks for the advice given here, especially the suggestion of using a trash bag to keep the water from entering. That plus the earmuffs gave me ZERO water coming in.

The new pump is half brass and half ABS. I will hang onto my old brass one in case the ABS part gives me trouble.

I might have paid a shop to do this but the down time durring the season would have been too much for me.

I now know more than I did before. :D