The fuel sending unit for the gauge is a float attached to a potentiometer (variable resistor). Depending on where the float is will determine the resistance, and thus the indication on the gauge. No fuel actually flows through the sender to the carburator.
Depending on the model year of tank, there may be 2 to 3 tubes coming off the tank; one for the actual fuel, a vent tube, and sometimes a return tube from the fuel pump. Make sure you're hooked into the right tube. Hope this helps.
Originally Posted by moner
there is not a single thing you said i disagree with. 100% right.
Love of Theory is the Root of all Evil.
I dream about the day that the average would-be rapist is afraid to approach a woman who's walking alone at night. I dream of the day when two punks talk each other out of sticking up a liquor store because it's too damn risky.