[Jrainman]

the sending unit .first disconnect the fuel lines off the sending unit then electrical wire, you will see a locking ring surounding the sending unit, tap it with a blunt scrwdriver or punch, move the ring from the tabs that hold it in,then pull sending unit

I think you will need to give more information about your truck engine size, carburator brand 2 or 4 barrel , did you check your fuel filter , was the fuel pump changed is it putting out the right amount of pressure for the carb you have .

im no expert but you might be headed in the wrong direction you might be getting to much fuel but you would need to fill in the blanks before getting some good advice here from the carb guys