What I would do is, take the connection from the tank at the input of the pump off. Take a hose the right size and put it from there into a 1 gallon gas can with some gas in it. Crank it over. If it draws gas from there, the problem is from the pump back. If not, the pump is likely no good. It is an engine mounted pump, right?
I wonder if common sense will ever make a comeback?