Fuel gauge & sender question

[charliez]

Now a problem with the fuel gauge. When filling tank it over filled but was showing 3/4 only never went above 3/4, using boat several times . Checking resistance seems fine at the sender having over half full, & empty readings, the gauge goes to full when the sender & ground are shorted. One other thing checking voltage at the gauge I have 12volts on ignition connection & around 10 on the sender side is this correct? Now I have pulled tank from boat dumped out all old fuel took sending unit out hooked back up to power & works great ( move the arm up gauge gauge goes to full & down -empty back & forth working smooth). The boat did set a couple of years & the problem started after that I am wondering if it was just stuck gummed up or maybe a bad connection . So should I put it back together & see what I have or dig further? Thanks Al

 

[Silvertip]

Re: Fuel gauge & sender question

Voltage on the SEND terminal is of little value. RESISTANCE on the send wire is of importance. 240 ohms empty, 109 ohms 1/2 full and 33 ohms full. Those are approximate numbers. If the gauge doesn't show full when the tank is full then the float arm needs adjusting or the float itself is saturated with fuel (heavy) and doesn't float well. Besides, you want the gauge calibrated so it reads EMPTY when the tank is EMPTY. You know when it is full because you are filling it. You cannot get precise empty, 1/2 and full readings. You can adjust for one of the three but not all three.

 

[charliez]

Re: Fuel gauge & sender question

Thanks, Well the system is about 17yrs old. What can you do if anything to the float if saturation is the problem other than removing it & drying it out or does it need replaced? Didn't seem all that heavy but I am not sure it was ok. Yes empty would be the adjustment I would want.

 

[Silvertip]

Re: Fuel gauge & sender question

Once saturated there is no drying it out. A new senders are not budget breakers at about $20.

 

[mistyice]

Re: Fuel gauge & sender question

Now a problem with the fuel gauge. When filling tank it over filled but was showing 3/4 only never went above 3/4, using boat several times . Checking resistance seems fine at the sender having over half full, & empty readings, the gauge goes to full when the sender & ground are shorted. One other thing checking voltage at the gauge I have 12volts on ignition connection & around 10 on the sender side is this correct? Now I have pulled tank from boat dumped out all old fuel took sending unit out hooked back up to power & works great ( move the arm up gauge gauge goes to full & down -empty back & forth working smooth). The boat did set a couple of years & the problem started after that I am wondering if it was just stuck gummed up or maybe a bad connection . So should I put it back together & see what I have or dig further? Thanks Al

i had the same problem, took gas sending unit out of tank found float had a crack in it ,and was rusty replaced unit worked great