Fuel gauge only going to 3/4 when grounded?

Great! Thanks for that, I never knew they were adjustable. Is it as simple as moving the toothed lever with a small screwdriver, or such? I should have mentioned (but didn't, obviously) that i pulled the cluster to replace the speedometer a while back, and it was sometime after that the gauge stopped reading. Not sure if I caused it, or it was just coincidence, but I couldn't find where I might have screwed it up. Now to go find a 10 ohm resistor.