Another gas gauge problem

[Steve G.]

My 63 SWC had a malfunctioning gas gauge from the time I bought it, so last winter I had a reconditioned gauge and a new sending unit installed... I recently ran out of gas 'cause, guess what? The gauge said 3/4. I've been told this week my problem is likely the cheapo repro sending unit I had put in, but I am also told those are essentially the only ones available out there.
Is this true? Do I buy them in a six-pack now?

[Dave Suesz]

Easy to check...

Use jump wires to connect the sending unit without installing it. Slide the float from full to empty position, etc. If the unit moves freely, it should indicate full range. If not, either the sender or gauge is wrong. Usually, senders either work or they don't- not just sometimes. They only have one moving part, the electrical contact on the end of the arm rubbing across the surface of the rheostat winding. If you have full contact here, and free movement, it should work. Accuracy is another matter. The lower part of the C1 winding is tapered, because the tank is tapered. If such details are overlooked buy repro mfr., the best you can hope for is to adjust so the E and F are correct. It is always best to adjust the gauge and sender together for this reason.