Gas Guage works then pegs out and is stuck

I have a 1998 22' Stingray 4.3L mercruiser. The gas guage works fine then it will peg out either way past full or way past empty. Then it appears the needle is actually stuck. I pull the guage form the dash and can pry a screwdriver in the face of the guage and it releases the needle and the guage will work fine. Then it will happen again. What can be causing this "pegging" of the needle. My guess is something electrical but I have cleaned the connections and checked the wiring. The only thing I have checked is removing the wires from the sending unit and cleaning. Its just odd that it works fine for hours and then happens then I fix it and it works fine..then it happens again.

Re: Gas Guage works then pegs out and is stuck

The usual cause of this is the sending unit which is just a variable resistor that changes as the float goes up and down. I would replace it, they are not too expensive and there are generic types that you can adjust to fit your tank. Just make sure you get one that matches the resitance required by your gauge.

Re: Gas Guage works then pegs out and is stuck

I had trouble with the gas gauge on my 17' tournament boat. After running out of gas when the gauge said 3/4 full I investgated. The float in sending unit was sticking -- It would not move up and down easily. I added more weight to the arm (used a crimp-on lead weight from the tackle box). The gauge reads better now and sticks less now than before.

Re: Gas Guage works then pegs out and is stuck

If you can pry on it and it works, I would lean toward the Fuel Gauge being bad, as this has nothing to do with the sender doing it's job. Just my opinion. Of course, the sender can cause erratic readings, but it's the prying on it and then it works that sticks in my mind. You can replace the sender cheaply enough to rule that out.

Re: Gas Guage works then pegs out and is stuck

Rick...not sure why you responded about a tach, the problem is with the fuel guage. I would still suspect the sender as that is what goes usually.

Re: Gas Guage works then pegs out and is stuck

Yeah, my mind was somewhere else when I typed Tach. Same answer applies, except I meant the fuel Gauge and of course, forget the dealer loaning one out.. Thanks Bob for the heads up... I will revise my reply...

Re: Gas Guage works then pegs out and is stuck

Hold it there for a moment. Fuel guage sending units rarely go bad, the actual guages crap-out all the time, but the most common reason that the guages go south is that the wires between the sender and the guage corrode, particularly the ground wire that will attach to the sender, usually by a little tab right next to the center pole on the sender where the data wire (shold be pink) connects.<br /><br />As to the cost, generic sending units (what are they, 30~240 ohms or something like that?) made by Tempo are availble all over the place and run around $30 or less. Guages are priced all over the place but I usually buy them from Surplus Unlimited where I think I paid about $15 for the last one I bought. For whatever its worth I have three gas tanks. I have found that guages last about 3 years, so I end up replacing one pretty much every winter. Wireing corrodes faster than you might immagine, particularly that negative wire, and I have replaced so many fuel tanks wire sets that I lost count decades ago. As far as senders go, I think the last one I replaced on our boat was sometime around 1994 and I'm not too sure now that the old one was really bad.<br /><br />Thom

Re: Gas Guage works then pegs out and is stuck

I am not sure what is causing it to peg out, but I found it just takes a tap on the glass for the needle to be freed and go back to normal working position.