Have a 1993 top gun and one of the fuel gauges stay pegged out in the full position when i turn the key on and start the engine. When you turn the key off the gauge returns to the empty position. Dont really want to pull the sending unit out if i dont have to . Has anyone ever had a problem like this and found a quick fix.If i was a bad float on the sending unit i would think it would always stay on empty.

Use an Ohmmeter to verify the resistance of the sending unit output at the tank with with the leads to the guage disconnected. There are two standard ranges, 0-90 Ohms and I believe 20 - 240. The low end of the range is full tank. You can short the leads going to the guage to test that. Should produce a full reading when shorteed and an empty one with them connected to nothing.

You may have a shorted sending unit producing the full reading.

http://www.diy-boat.com/content/view/88/49/

Check the ground wire to the back side of your fuel gauge. My fuel gauge was doing the same thing when I noticed my ground wire feel off.

It's definitely a bad ground, I'd say a wire probably and not the gauge

A bad ground ground would result in an open circuit and that would produce a constant empty reading, not full.

A bad ground ground would result in an open circuit and that would produce a constant empty reading, not full. I just went through this whole process after installing a new fuel tank. The troubleshooting process is pretty straightforward. I agree it's not the guage but most likely a bad sending unit or a hot (usually pink) wire shorted to ground.

Not in my case. I had no ground wire and when I turned the key on the gauge would go to full, once I attached the ground wire it went back down to 1/4 tank of fuel (which is the amount I had in the tank).

Hi,

My gauge is also showing full tanks, on either tank.

So I assume I must have a ground issue under the dash?

Will look this weekend.