Sounds like the diaphragm in the pump might be weak, or gone. As mentioned, take the line off at the carburetor & put it in a fuel can, then have someone turn the starter over & see what you have fuel wise.
I think I agree. I had a pump go bad. When I put the inlet on a vacuum gauge and pumped it by hand, it would show suction, then it would not hold the vacuum. It could move fuel, as long as there was no air in the line. Once it was empty, it couldn't really move anything along.
On the new pump, it held vacuum between pumps.
I guess you can disconnect the inlet to the pump, and put a vac gauge on it, and see what it does after a few cranks.
