# fuel gage failure



## flydunker (Sep 20, 2000)

My fuel gage in the boat always says full, which would be nice if it were true but it is not. can someone assist me in how I may trouble shoot the issue to find the problem.


flydunker


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## TONGA (Jul 22, 2002)

A built in tank and dash mount gauge,,,check your ground at the gauge and at the tank,,,it's possible the float on the sending unit is just stuck but I doubt it


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## el Cazador (Nov 10, 2000)

We have a 1980 Glastron that never reads a fuel level. The guage just bounces between full & empty, constantly moving, regardless of actual fuel level. Any thoughts on what I can do to fix it?


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## TONGA (Jul 22, 2002)

I take it you mean it bounces even if the boat is dead still,,if so then more than likely its an electric issue and more than likely the ground...what I would suggest you both do to verify is make up a jumper and run it from your sending unit ground to the negative post on your battery. and see if your gauge works right..you know nothing fancy just make good contact with the neg post and the sending unit and see if it clears up the problem,,,if it dose then you can look into why your existing ground is not making a good connection,,,if it dose not then we can look elsewhere for the problem.


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## Burksee (Jan 15, 2003)

FD, if yours is always reading full it may be a shorted somewere between the tank the gauge. Take the lead off at the gauge and see what happens.

EC, yours sounds like it has a bad ground or gauge, especially if this is occuring while standing still.


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## el Cazador (Nov 10, 2000)

TONGA said:


> I take it you mean it bounces even if the boat is dead still,,if so then more than likely its an electric issue and more than likely the ground...what I would suggest you both do to verify is make up a jumper and run it from your sending unit ground to the negative post on your battery. and see if your gauge works right..you know nothing fancy just make good contact with the neg post and the sending unit and see if it clears up the problem,,,if it dose then you can look into why your existing ground is not making a good connection,,,if it dose not then we can look elsewhere for the problem.


Yep...we can have the boat up on the hoist and turn on the instrument panel and all that fuel guage does is bounce around. Forgive my ignorace, but what do you mean by "sending unit ground"? Where would I find this? It's a 1980 Glastron SSV-167 we inherited when we bought our cottage.

Thanks, eC


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## Burksee (Jan 15, 2003)

EC,

I'm not familiar with the exact make up of your boat but most fuel tanks will have two wires going to the sending unit. One will be the 12V "power" feed thats coming from the gauge; the other will be the ground. The sending unit is actually a type of variable resistor that controls the grounding of the fuel gauge. To distinguish between the two unplug both and use a 12v test light or volt meter to determine which is power, which is ground. Any interruption in the ground circuit will cause the gauge to read inaccurately or not at all. By running a ground directly from the battery (NEG/-) to the sending unit ground you are eliminating any issues in between the two. Loose connections, corrosion in the wiring or any of the connectors can cause this as well. Usually if the sending unit itself goes bad it will either cause the gauge to hold at one end or the other, not cause a fluctuating reading.

Good Luck!


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## el Cazador (Nov 10, 2000)

Ok...I'll check it out tonight at I'm heading up to the cottage after work today.

Thanks for your help!


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