Fuel Gauge

[Ski213]

My fuel gauge is crazy. Like most I've dealt with on anything, the gauge isnt balanced. The top half (on gauge) is alot more fuel than the bottom half. This one is over the top though. 52 gallon tank. Reading less than 1/8 tank it still has 22 gallons on board. When the tank is full the gauge bounces, while the boat is stationary, back and forth so I'm guessing something is wrong. The needle stabilizes once the gauge starts dropping. Curious if this is pretty standard and I'd be wasting my time trying to troubleshoot. It is a late 90s stratos.

[BKeith]

With mine empty to the point the pickup will not provide fuel to the motor, 12 gallons puts mine just a tick past1/8 tank, and has about seven gallons left it can pump out when it first gets to empty.   I don't remember but I think it's a 48 gallon tank.  It's probably been eight years since I've filled it up.  As long as I know about how much is in it, I don't worry exactly where the gauge is, as long as it's consistent.  Pulling the sending unit though to adjust it is not much of an option on mine and I don't think you have access to yours either.

[junyer357]

Ours has not worked in years. Tank will be full and it wont show 1/4 tank. Ours is under the seats and has no access or even a way to see it. What works for us is to keep the boat full, and refill it after a trip or two depending on how much we run it. It also keeps the expense to a few gallons every so often over 40+ gallons at a time, plus little room for vapor to condense and get water mixed in.

[Ski213]

Mine was consistent but not anymore. Im not sure what changed. I can kind of keep track of what's roughly in it based in how much running I've been doing. Filling every time is a good idea but its not something I always do. If 1/8 tank always meant 22 gallons left I wouldn't worry about it. It's the fact that it could be 12 gallons left today and 22 left next time. I premix so it screws the ratio up a little as well since I always add the oil first. My tank is under the seats, I have to take the whole piece that the seats are screwed to off, so it is accessible for me, although not a ton of fun to get to.

[BKeith]

Yes, but isn't yours and L shaped tank with the sending unit in the top, right under that section of rear deck behind the seats. I know I looked at trying to help a friend with a 201's sending unit and after a little probing, I told him to have fun, he was welcome to try and fix it if "HE" wanted to, I would even let him use my tools.

[Fishing Rhino]

I wonder how much of a problem condensation is.  We don't worry about it in our cars.

 

When I was a kid, all cars had a glass "fuel bowl" before the carburetor.  Its purpose was to trap water before it could get to the engine.  The looked something like this.

 

 

You would loosen the threaded wheel just below the bowl enough so you could get the glass cup out to dump the contents and clean the bowl.  I think the last car we had with a fuel bowl was a '49 Mercury.  I don't recall seeing much water, though it did collect crud from the tank.  There was usually a tiny amount of sediment in the bowl, but not much more than a drop or two of water, if that.

 

I had a Racor water separator, fuel filter on my lobster boat.  It had a clear plastic bowl with a petcock on the bottom to drain water.  I don't recall getting water in that either. 

 

The biggest problem when you got water in the tank came with cold weather.  The water would freeze.  If it was in the wrong place, or the right place it would plug the line so fuel couldn't flow.  In the winter, it was common to add gas line antifreeze to your gas tank.  Today not so much, if at all.

 

Back in the day, underground tanks would develop leaks, allowing water into the fuel, and some may have leaked into the tank from the fill covers.  I suspect that water in your gas tank back then came with the fuel when you filled up, not so much from condensation.

 

I'm not saying there is no condensation.  Metal tanks will be most prone to condensation, while plastic or fiberglass are less susceptible to condensation.

 

Water in the fuel can destroy a diesel engine.  While fuel oil will pass through the tiny holes in the tip of an injector, water will not.  It will blow the tip off the injector.  Another way that fuel can be contaminated with water is if the tank vents are poorly designed.  Spray or water can slosh into the vent cover and work its way into the tank.  A boat vent should always have at least one coil in the line so that air can pass by without carrying some water into the tank.

[Ski213]

Oh crap I think you're right. It's definitely under that section of rear deck. That section of deck comes off with the seats but now that you say that I'm thinking there's something else between it and the tank. I had it off awhile back making sure the person who installed the new seats hadn't run the screws into the tank but I can't remember for sure. I'd say it would be exactly the same as your friend's 201. Living with the gauge as is is sounding better by the minute.

[Klebs01]

I was just pondering this issue on my boat. I supposedly have a 27 gal tank, but have never filled up more than 15. I'm wondering if I'm not filling it up all the way or if th gauge just reads empty with about 12 gal left.

[BKeith]

Best way to find out, with the boat sitting on the trailer, undo the primer bulb, put a piece of hose on it and feed it into some five gallon jugs on the ground.  Pump the bulb and get you siphon going.  When it stops draining, your are at the level the pickup in the tank is going to no longer let the fuel pump pull fuel.  When you start putting the gas back in the tank, watch the fuel gauge so that just as it moves at the empty mark, take note of how many gallons it took to make it wiggle on the empty mark, then how much it takes to get to the next mark up.  Have the boat at about the same attitude it would be in the water doing this.

 

I know with my boat 1/8 tank mark is 12 gallons.  Empty mark is seven gallons.  Pay attention to about how much you burn an hour and you know about how long you can run after it gets on empty before the pucker factor starts kicking in.

[Ski213]

Best way to find out, with the boat sitting on the trailer, undo the primer bulb, put a piece of hose on it and feed it into some five gallon jugs on the ground.  Pump the bulb and get you siphon going.  When it stops draining, your are at the level the pickup in the tank is going to no longer let the fuel pump pull fuel.  When you start putting the gas back in the tank, watch the fuel gauge so that just as it moves at the empty mark, take note of how many gallons it took to make it wiggle on the empty mark, then how much it takes to get to the next mark up.  Have the boat at about the same attitude it would be in the water doing this.

 

I know with my boat 1/8 tank mark is 12 gallons.  Empty mark is seven gallons.  Pay attention to about how much you burn an hour and you know about how long you can run after it gets on empty before the pucker factor starts kicking in.

That's a heck of an idea man. I appreciate it. I'm gonna have to do that. Be good to know where pickup stops. I guess that's true empty even if there's 10 gallons that can't be picked up. So long as the gauge is consistently wrong I can work with that if I have an idea of where I'm at at a given mark on the gauge.

What you're calling the pucker factor I've always called gas roulette. I'd imagine that a two stroke outboard doesn't respond well to being run out of fuel at 6 grand.

[Sam]

Ski, please consider the Power Squadron's recommendation regarding fuel:

 

One-third of the tank going out.

One-third of the tank coming in.

One-third of the tank in reserve.

 

Now you have to estimate each level of fuel and mark the gauge with a Sharpie for each third.

[Ski213]

Ski, please consider the Power Squadron's recommendation regarding fuel:

 

One-third of the tank going out.

One-third of the tank coming in.

One-third of the tank in reserve.

 

Now you have to estimate each level of fuel and mark the gauge with a Sharpie for each third.

That's good advice. I always error on the side of caution. The way my luck runs the trolling motor would crap out as soon as I ran out of fuel for the big engine and there I'd sit.

  

I wonder how much of a problem condensation is.  We don't worry about it in our cars.

 

When I was a kid, all cars had a glass "fuel bowl" before the carburetor.  Its purpose was to trap water before it could get to the engine.  The looked something like this.

 

 

You would loosen the threaded wheel just below the bowl enough so you could get the glass cup out to dump the contents and clean the bowl.  I think the last car we had with a fuel bowl was a '49 Mercury.  I don't recall seeing much water, though it did collect crud from the tank.  There was usually a tiny amount of sediment in the bowl, but not much more than a drop or two of water, if that.

 

I had a Racor water separator, fuel filter on my lobster boat.  It had a clear plastic bowl with a petcock on the bottom to drain water.  I don't recall getting water in that either. 

 

The biggest problem when you got water in the tank came with cold weather.  The water would freeze.  If it was in the wrong place, or the right place it would plug the line so fuel couldn't flow.  In the winter, it was common to add gas line antifreeze to your gas tank.  Today not so much, if at all.

 

Back in the day, underground tanks would develop leaks, allowing water into the fuel, and some may have leaked into the tank from the fill covers.  I suspect that water in your gas tank back then came with the fuel when you filled up, not so much from condensation.

 

I'm not saying there is no condensation.  Metal tanks will be most prone to condensation, while plastic or fiberglass are less susceptible to condensation.

 

Water in the fuel can destroy a diesel engine.  While fuel oil will pass through the tiny holes in the tip of an injector, water will not.  It will blow the tip off the injector.  Another way that fuel can be contaminated with water is if the tank vents are poorly designed.  Spray or water can slosh into the vent cover and work its way into the tank.  A boat vent should always have at least one coil in the line so that air can pass by without carrying some water into the tank.

I probably need to pump my tank empty. I doubt that its ever been done and I'm sure there is bound to be some water in there. Whether from condensation, splash through the vent, or both.

[Al Wolbach]

I wonder how much of a problem condensation is.  We don't worry about it in our cars.

 

When I was a kid, all cars had a glass "fuel bowl" before the carburetor.  Its purpose was to trap water before it could get to the engine.  The looked something like this.

 

 

You would loosen the threaded wheel just below the bowl enough so you could get the glass cup out to dump the contents and clean the bowl.  I think the last car we had with a fuel bowl was a '49 Mercury.  I don't recall seeing much water, though it did collect crud from the tank.  There was usually a tiny amount of sediment in the bowl, but not much more than a drop or two of water, if that.

 

I had a Racor water separator, fuel filter on my lobster boat.  It had a clear plastic bowl with a petcock on the bottom to drain water.  I don't recall getting water in that either. 

 

The biggest problem when you got water in the tank came with cold weather.  The water would freeze.  If it was in the wrong place, or the right place it would plug the line so fuel couldn't flow.  In the winter, it was common to add gas line antifreeze to your gas tank.  Today not so much, if at all.

 

Back in the day, underground tanks would develop leaks, allowing water into the fuel, and some may have leaked into the tank from the fill covers.  I suspect that water in your gas tank back then came with the fuel when you filled up, not so much from condensation.

 

I'm not saying there is no condensation.  Metal tanks will be most prone to condensation, while plastic or fiberglass are less susceptible to condensation.

 

Water in the fuel can destroy a diesel engine.  While fuel oil will pass through the tiny holes in the tip of an injector, water will not.  It will blow the tip off the injector.  Another way that fuel can be contaminated with water is if the tank vents are poorly designed.  Spray or water can slosh into the vent cover and work its way into the tank.  A boat vent should always have at least one coil in the line so that air can pass by without carrying some water into the tank.

I installed a fuel/water separator on my Champion and my pontoon boat came with one from the dealer. I was told Yamaha requires one to be installed on new outboards for the warranty to be honored(not sure about this statement).