Fuel guage not working on my boat

[HaywardBound]

Boat is a '97 Crestliner 1850 SportFish with a 115hp Johnson 'Faststrike', and the fuel guage does not work.

I took out the sending unit, hooked up a new one and it still does not work.

I checked the voltage at the sending unit, and there is either no voltage, or very little, like 1 volt. (I don't know what the volts should be).

Also double checked the fuses, and they are all good.

Any other ideas I should check out? I'd really like to have this guage working.

Thanks.

[Valv]

Don't apply voltage to sending unit !!! I works with negative, not positive.

Faster way to find out if it works it connect a light to positive of battery and negative to pink wire of sending unit, lift float up and down and check light if it gets brighter.

If you need the gauge send me a picture, I have most of the the Crestliner's and mine are only $ 4.50

[HaywardBound]

Thanks, Valv...

I didn't apply any voltage to the sending unit, just used a multimeter on it and it did not show any voltage.

I'm not sure what you mean when you say 'It works with negative not positive'....

About the light thing...do you mean any 12 volt light bulb, or a test light?

Thanks.

[waskawood]

The sending unit in the tank is on the "negative" side of the circuit. It is on the negative side instead of the positive side because in theory it should be less apt to cause a fire if there is a short circuit. Any incandescent bulb should work as long as it is 12 volts. You can use your voltmeter as well. Place the positive lead of the voltmeter to the positive terminal of your battery and the negative lead as Valv explained. Your voltmeter will now work like an uncalibrated fuel gage. THIS SHOULD ALL BE DONE AWAY FROM THE FUEL TANK JUST IN CASE THERE IS A SPARK!!!

[Valv]

As waskawood said it's actually much better than a light.

The sending unit is a "rheostat" it will let Neg from battery pass through depending on position of float.

If you hookup voltmeter red to + Batt and black to pink wire you should see more or less voltage going through depending from position of float.

Also,to check gauge try to touch Neg (black wire) with pink wire, needle should go to FULL position immediately.

[HaywardBound]

Thanks for the advice!

Valv, first I checked the guage as you said by connecting the black and pink wire. Nothing on the guage. I did this at the sending unit, but away from the tank (jumper wires).

I have two connections on my sending unit: Pink.... and the other terminal has black and 2 green wires, all connected together.

I have hooked up a new sending unit and that did not do anything, so I don't think it is the sending unit. (I didn't do the light test yet).

Should I check the voltage at the guage, or cross the pink and black wire AT the guage?

Any advice?

Thanks in advance.

[Valv]

Do both tests at gauge, you need power + (with key on) at purple wire on gauge. Then jumper negative (black) to pink, gauge should read full otherwise it's shot.

Send me a picture of it, to see if I have one.

[HaywardBound]

Thanks Valv, I'll let you know what I find out.