Just learned this with my Hunter 28.5. The circuit is fairly simple. 12v to the meter through a fuse to the meter. From the meter it connects to the top of the float. The bottom of the float is then grounded.
Using a volt meter, measure from the ground on the engine control to both sides of the fuse, both sides should measure EXACTLY the same, if not, your fuse connection is bad (this was my problem).
Measure from the ground (same as above) to both sides of the meter, fore yours, I'm guessing that you will see the same voltage as at the fuse. Measure the voltage at the top of the fuel float. If that is 12v (or the same as what you measured at the fuse, then the float is open. If there is no voltage at the float (negative lead of the meter still at the ground at the engine control) then the wire from the meter to the float is open. Measure the voltage at the float ground, if it is 12v, then the ground wire is open.
Last, turn off tha boat DC switch and set your volt meter to the 2000 Ohms scale. Measure from the top of the float to the float ground. It should read somewhere between 250 to 25 ohms resistance.
You can google the fuel level meter circuits to get an idea of what the circuit looks like.
Hope this helps.
Mike
