Gas Guage Trouble

[jwoutdoors]

Mine was the exact oppisite, reading below Empty all the time. I did some research on how gas guage actually works. My first guess with mine was "is the float in the tank sticking?" I took the seats and floor panel out and checked it and the float was fine. From what I read from the trouble other people were having was that 90% of the time its the sending unit on the tank, because most of the time the guage doesn't just go bad. Mine just happened to be something simple like having the ground wire on the wrong terminal on the battery. The sending unit on the tank works off of resistance, meaning that when the float moves up and down as the fuel level changes in the tank, the resistance changes and thus moving the needle on your guage. I think I read that the scale for resistance on most guages is 240ohms being full (i thinnk) and 33ohms being empty. In order to test this you would actually have to move the float up and down while metering the resistance at the guage, and this would tell you if the sending unit is bad or not! I know it sounds like pulling teeth, but if you can get to the top of your tank pretty easily, it's really not that hard. I looked online at new sending units and they ranged from 30 - 50 dollars. I'm not saying that this is your problem, but this may help you troubleshoot. Wrenchin2 seems to know about everything there is to know about a boat, PM him and maybe he can lead you in the right direction! Hope this helps

 

[wrechin2]

Something is not right.......... if you ground it and it goes to empty. That sounds like a screwed gauge to me. The system works off resistance. The less resistance the sending unit offers , then the higher the gauge reads. When you apply full ground to it, it will peg the needle very hard and rapidly. That is why you shouldn't hold it but simply "scratch" the terminal with ground to verify needle movement. If everything is "normal" sounds like the gauge is backwards. Also check the terminal connectors on gauge. "I" is for "igniton" and "S" is for the sending unit. "G" is for ground. If you remove the wire off of the "S" and it stays full, it is a bad gauge as they default to empty. Hope this helps....