I am out of ideas. The fuel gauge reads E when it is full and F when it is empty. Original owners said it has always been that way. It is an after market Stewart Warner Deluxe unit which is a 240-33 Ohm gauge, industry standard on the marine sending unit in the tank is also 240-33 Ohm. I tried reversing the wires on the gauge thinking it was an easy fix, it did nothing.

I am thinking it is a polarity issue, but may be headed down the wrong path. The gauge is connected to the center post on the sending unit, there is a second spade on the tank at the sending unit, but nothing connetced to it. There is a seperate ground tab welded mid-tank that has a ground wire attached.

thoughts?