1995 Four Winns fuel gauge issue

[anderdea]

I had the interior out of my boat so I decided to replace the gas tank sending unit as it was reading low. On a full tank of gas it reads 5/8 of a tank. The replacement reads the same thing. Empty is well below the "E". The gauge pointer is on the little gas pump with about 4 gallons left. Anyone have any ideas on how to make it read accurately? Is the an adjustment on the back of the gauge? There isn't an access though the front gauge cluster.

 

[tpenfield]

No adjustment. It probably is that the sender and the gauge are not matched in terms of their resistance. Some senders go to 90 ohms and other types go to 240 ohms, if I recall correctly.

 

[kjsAZ]

Sender resistance attached. For North America they should be all the same but sometimes it's not....

 

[anderdea]

Kind of figured it was the resistance of the sender unit. That's what I get for purchasing a generic sender. Unfortunately I has to take out the interior to get to the tank so that's not going to happen. I may try playing with some inline resisters as I can get to the wires.

 

[Silvertip]

That won't work and you very likely have the correct sender. Disconnect the pink wire from the "S" terminal on the gauge. Using an ohm meter, measure resistance from the wire to ground. If you have a rough idea how much fuel is in the tank, use the following numbers as a guide for calibration. full tank 30 - 35 ohms, 1/2 tank 100 - 105 ohms, empty tank 240 ohms. Calibration can generally be done by bending the float arm. If the gauge is reading low, bend the arm down. If it is reading high, bend it up. Calibrate for EMPTY -- not FULL. You know when the tank is full because you filled it. You want to know when it is empty. You can calibrate a sender for best accuracy at only one point (it's physics).

 

[anderdea]

Silvertip, thanks. Next time I take out the interior I'll try your suggestions. Just need to get it back in the water. Live on Cape Cod and have only used it once this year due to oil pan leakage issues.