fuel gauge playing up

The fuel gauge indicator on my xu-1 is on full and wont budge. Drove to Winton last weekend and put 70 litres in the tank and since then it's staying on the full mark. It would be great if it didn't use any fuel from Winton to Wagga but I doubt it. I have fiddled with the wire on the sender unit (no go)...anyone got ideas please???

cheers,
scooter

check the resistance of the sender unit with the wire disconnected with a multimeter and compare to specs, it that isnt out of wack it may need a new voltage regulator in the dash cluster, they shit themselves!