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jfw432

Fuel gauge at idle vs at speed

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jfw432

After boating today in my 2000 Response, I'm starting to get a little concerned about how much fuel I really have. I have one of these fuel senders and I realize it's in the back of the tank so it will always show more on plane than stationary but I've never seen this large or a difference. The arm on my fuel sender is probably only 4 inches long. I fixed it...I didn't cut it initially. (http://www.amazon.com/Sierra-90424P-4-24-Sender-Package/dp/B000Y8A0MQ/ref=sr_1_3?ie=UTF8&qid=1438225439&sr=8-3&keywords=fuel+sender).

When the boat is on plane, I show 1/2 tank but when I'm stationary with 4 average sized people in the boat (1 person up front, 1 in the back seat, me driving, and 1 in the observer seat), the gauge is showing 1/8 tank or less. That's a pretty vast difference.

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Falko

I get about a 1/4 tank swing on mine. Or I did, but the gauge or transducer or connection seems to be failing lately and I get some erratic and low readings.

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Mackie 12

The gauge on sportster has never really worked, my rule of thumb is anything below half I keep my fingers crossed.........

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jfw432

Yeah below half is kinda iffy to me now but I like to keep weight down when possible so I'd rather not have 20 gallons of gas at all times as a just in case.

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iliketoski

My 2000 VLX varies widely (I even tried replacing the float), my rule of thumb is if it is looking low/empty at idle, I'm in trouble if I take off and it doesn't go to at least 1/3 tank before planing. Its a difficult situation with a large flat tank.

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MadMan

My solution has been to never look at the gauge while moving.

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jfw432

Ok so the idle fuel reading is more accurate than the planed off reading?

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robbennett

Best gauge is to look at the side of the tank and see how much is in there. Mine says less fuel when the bow rises because the gauge is at the front of the tank and fuel naturally shifts to the back on acceleration.

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jfw432

I don't think I can see the side of my tank even when all the liners and carpet are out.

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iliketoski

On V-Drives, the float is in the rear of the tank (and its under the floor, so you can't see it), so when the bow is up it reads like there is lots of fuel. If I'm reading 1/3 of a tank with bow rise, I know I don't have much.

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jfw432

On V-Drives, the float is in the rear of the tank (and its under the floor, so you can't see it), so when the bow is up it reads like there is lots of fuel. If I'm reading 1/3 of a tank with bow rise, I know I don't have much.

Same with the direct drive only it's under the floor in the rear trunk.

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grandude

On a direct drive boat the tank is above floor level and runs side to side rather than front to back. The fuel level reading is basically the same on plane or off plane. if your getting an incorrect reading you may need to replace the sending unit. The float can get saturated and not float up and down as it should. It's 15 years old at this point. With all the moisture in ethanol fuel it can happen quicker. Replace the sending unit and you'll likely get much better results.

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jfw432

On a direct drive boat the tank is above floor level and runs side to side rather than front to back. The fuel level reading is basically the same on plane or off plane. if your getting an incorrect reading you may need to replace the sending unit. The float can get saturated and not float up and down as it should. It's 15 years old at this point. With all the moisture in ethanol fuel it can happen quicker. Replace the sending unit and you'll likely get much better results.

Normally I'd agree as my last boat had the same sending unit but the tank is only 4-5 inches deep at the back where the float is instead of twice that like most tanks I've seen. The fuel sending unit is in good operation and it's not the original. It's not saturated either.

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justgary

The main problem seems to be that these tanks are relatively long and flat, but have no baffles. The fuel is free to slosh back and forth, making the sender float move all over the place. The slosh is pretty much constant when the boat is on the water, so unless you rig a very good baffle around your sender, you will continue to see wild fuel gauge swings.

By very good baffle, I mean nearly sealed off so it has a very low time constant of maybe a few seconds.

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jfw432

Maybe one of these days I'll just take 5 gallons with me in the boat and run the tank until it's empty to see what is really empty.

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MadMan

Maybe one of these days I'll just take 5 gallons with me in the boat and run the tank until it's empty to see what is really empty.

I did this when winterizing, I've always pumped my tank dry. Then, next season 1st fill-up, I stop every 5 gallons and read the gas gauge to see how it tracks.

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iliketoski

I did this when winterizing, I've always pumped my tank dry. Then, next season 1st fill-up, I stop every 5 gallons and read the gas gauge to see how it tracks.

This is a great idea, one question, do you fill up on the water? If not I'll bet the boat sits different on the trailer versus in the water.

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