Going further than full, to say the 3 o'clock position, is an open circuit on the ground side. Check the ground connection on top off the tank.this will be a push on post style connector, then follow that wire to the frame, check that. Then make sure the pink wire from tank/fuel selector valve if you have dual tanks, is not broken. Check ground side of resistor and then check ground pin on gauge. Any bad connection will result in going past full.