First thing is to make sure the wings are bonded (grounded with a ground braid) to the fuselage. The studs for this are located near the front spar under the top wing to fuselage fairing strips.

Larry,
I'll take a look at the ground on both wings, I did see that in a previous thread. Although the lack of guages forces me to be more diligent about the burn per hour vs flight time, I'd like to have the guages workin and I may put in a fuel computer of some sort but not sure how well the work with non-injected engines. I try to be anal about fuel. Are the sending units typically problematic?
Will

Willie,
Not usually,but they may be 70 yrs old now and have worn down where the wiper rubs the resistor and become intermittent. The originals are the same as pipers of the era and cessnas too except arm and float length which is customized to the specific tank. But check all the connections first and sometimes there may be markings on the outer plate of the sensing units. The originals wqere stewart-warner I don't recall the brand name of the incompatible Univair replacements but I think I have one. Univair also sells a new gauge that is compatible but you have to use both tank sensors. However, it is also possible that someone has replaced one sending unit with the currently available ones from Univair and they are not compatibile with the gauge unit