In article , Yossarian
wrote:

I understand that functional fuel gauges are required equipment for day VFR
flight. Yesterday during my preflight in a 172 I saw that the right gauge
was functioning intermittently--it would show full, flicker down to zero,
bounce around, etc. Tank was visually confirmed full. Mechanic messed
around with it for a while to no effect.

I believe certification only requires that the gauge show empty when
the tank is empty.

Would you fly this airplane?

If you have visually checked the fuel quantity and know approximately
what your fuel burn is, (you do fly by your watch don't you?) you
should be good to go.
I was going to say that my Champ doesn't have a gauge, but then I
remembered there is and I think it is off a Model A Ford. Of course, in
a Cub it is just a wire in a cork sticking up through the cap.