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thinkxingu
05-14-2016, 07:34 AM
Hi! How much faith do y'all place in your gas gauges? I know they can waiver with movement, but are they fairly reliable when stable? What's a good level to be running down to?

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VitaBene
05-14-2016, 08:54 AM
Mine seems to be pretty accurate sitting or on plane. Check yours by filling when showing half, then calculate actual from used. Then fill at 1/4 and check. I try to stay at a quarter min.

I rarely fill to save weight. Gas weighs 6 lbs per gallon, so for me I save 300 pounds by not filling.

thinkxingu
05-14-2016, 08:55 AM
Mine seems to be pretty accurate sitting or on plane. Check yours by filling when showing half, then calculate actual from used. Then fill at 1/4 and check. I try to stay at a quarter min.

I rarely fill to save weight. Gas weighs 6 lbs per gallon, so for me I save 300 pounds by not filling.
Good ideas, thanks!

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Slickcraft
05-14-2016, 09:34 AM
After a few fill-ups I calculate an average number of gallons/hour for our usage and then go by hours since last fill.

I also have noted the # gallons for a fill and the gauge level prior to the fill. I found that the gauge overstates the remaining fuel.

DesertDweller
05-14-2016, 10:25 AM
To answer your question, some gauges are a lot more accurate than others. For me, mine is fine when stationary but once I get up on plane it drops off like there is no gas it in. I also follow the quarter tank policy. Once it gets to a quarter tank I will put gas in it.

Descant
05-14-2016, 11:12 AM
Part of the accuracy may depend on the shape of the tank. Old round tanks would stay at 1/2 full forever and as you got to the round bottom, the gauge dropped quickly. Also depends on "usable" fuel i.e. how far off the bottom is your pick up? Varies from mfg to mfg.

I used to ad fuel at 1/4 and fill to 3/4 depending on cruising plans. That kept the weight down and leveled the spending pattern. A few years ago, the marina manager said that's what most people did. Then people started filling all the way to get as much fuel on board as possible before the next price increase, and they cruised less, anchored more.

I also had a time frame where the gauge didn't work, so as Slickcraft suggests, I watched the hour meter.

My father used to own a 1950 CC 30' Cruiser. No gauges, no hour meter, but the tank fill was a straight pipe and we had a measuring dipstick. Marine gas was $0.35/gallon, I think, and the friend who said "Let me pay for the gas" wandered off as the pump went above $15.00.

noreast
05-14-2016, 12:14 PM
The good news is they usually read less than you have,or at least my last few have, I was way low a few times and actually had at least 5 gallons left.

thinkxingu
05-14-2016, 01:20 PM
Filled up at half today and took 20 gallons, which echos the post above about reading over (we have a 42 gallon tank). Looks like I'm good down to 1/4 tank. Thanks!

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NoBozo
05-14-2016, 02:23 PM
I had a 20 foot Donzi with a 350 SBC that burned 3.5-4.0 GPH at cruise and just putting around. One of my very first trips ended.. Out of Gas after dark and a mile from the ramp. Wilderness on shore. Picture two guys with canoe paddles paddling for a couple of hours...one guy on each side of the rear seat hanging over the side. Good thing we had beer....and canoe paddles. :D The gas gauge was about HALF with the needle "bobbing".

From then on I kept close track of the hour meter at all times, and I kept a log book of how many gallons I added at each refueling. Generally I would start thinking about the gas dock when the gauge needle got down to 3/4 mark with the needle "bobbing'. With a full tank the needle would stay pegged for quite awhile (hours) before bobbing down toward 3/4. At that point: "Lets go for gas." :look: NB

PS: I never ran out of gas again.

Dave R
05-14-2016, 06:04 PM
I removed the gas gauge on my boat and put a Lowrance LMF200 in place of it. I also put in a fuel flow probe a a spoeed sensor. Now I have a ridiculously accurate gas gauge and I can see my actual MPG in real time so I can can tweak my throttle and trim to maximize fuel economy. Very handy on long trips.

upthesaukee
05-14-2016, 08:20 PM
I fill up at half a tank. When I am at the dock, the gauge appears to be pretty accurate.

Why at half a tank, you might ask. With my Sunbeam Corsair, with a 135 Optimax, I had a 30 Gal tank, but I had Smartgauges, and the fuel flow was quite accurate. I used to run down to 20-22 gallons used, then head for the marina to fill up.

We got Upthesaukee Too, with a 58 gallon tank. When we got the boat, it had "some" gas in it. Looked like just under a half. We went out a few times, and decided to stop at West Alton to get gas on our way back to Parker's; gauge was just under a quarter tank. Gas at the time was up around $4 / gal. . It took 53 gallons. My wife gulped. We had a spell of nice weather, and used the boat quite a bit, and took it for a pretty good ride, and on the way home, we came to a stop in the middle of the lake to enjoy the day, and saw that it was again under a quarter tank. Had just enough time to make it to West Alton and filled up again. 49 gallons. Two $200 (roughly) fill ups in two weeks.

We got away from the gas dock, and my wife said we need to start filling up when we get down to half a tank; then it will only be $100 per fill-up. I told her that it didn't matter: filling up at 50 gallons every 2 weeks for $200 or every week or so at around 25 gallons for $100. She said that she didn't care...she just didn't want to see the $200 fill-ups. I said OK Admiral... because as we all know, a happy wife is a happy life. :cool::laugh:

Kamper
05-15-2016, 11:24 AM
I used portable tanks and calculated my burn at 5gph full-out. My fuel-gauge was my watch. A lot of people use this technique even if they also have more sophisticated equipment.

itchin for fishin
05-20-2016, 06:02 PM
I just went through that today. I had a boat on dry dock last summer and still had a 1/2 tank of fuel that I wanted to burn off before refueling. When I got to a 1/4 tank I called it quits since I once went below the quarter, and to my embarrassment, I ran out of gas as I went through Spindle Point. So long answer to short question, I trust it to a 1/4 tank.

joey2665
05-22-2016, 09:16 AM
I have a brand new Sea Ray and Irwin told me the gas gauges even with new technology are off by at least 25%. I never go under 1/3 of a tank

SAB1
05-23-2016, 02:39 PM
I tend to fill up when it drops a little under half, especially as the weather cools toward fall. Try to minimize condensation.

Bear Islander
05-23-2016, 03:10 PM
My gauge stays at full until the tank is about half empty. I think the tank is at an angle. When it indicates below 1/4 I am almost empty. I fill up when it goes under 1/2.

Phantom
05-23-2016, 03:11 PM
My gauge stays at full until the tank is about half empty. I think the tank is at an angle. When it indicates below 1/4 I am almost empty. I fill up when it goes under 1/2.

Have everyone sit on the other side of the boat ? :D:D:D


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