When I bought my 98 Alumaweld Intruder second-hand, the only thing that didn't work was the fuel guage. After pulling the access plug in the floor, I found that the wires leading to the sender unit were getting wet with salt water and condensation where they connected to the unit and had shorted from power to ground. The entire top of the sender unit was corroded and worse yet, the ground wire had actually started melting.

After replacing the wires, I picked up a new sender unit for about thirty bucks. The tricky part about installing the unit is getting the float adjusted since my tank is only about 4 inches deep. You need to bend and cut the float wire the proper way so the float doesn't hit the bottom of the tank, but still reads right. The guys at 3 rivers told me how to do that when I got the sender unit, but it still reads a little off.

Now I check the top of the sender unit for moisture regularily and also wipe the underside of the access plug down. It seems like there is always condensation there.