You should test for a blocked air vent in the gas cap by running your engine til it dies then loosen the cap and listen for air being sucked in. If you do hear the noise of air that means the vent is blocked and causing a vacuum.
The other test I would do is disconnect the fuel line at the carb and crank the engine. Gas should spray out and not just trickle. Obviously don't do that test with a hot engine. If you do need a fuel pump, I recommend getting one from stens or kohler rather than Amaz. The cheapest ones are pretty bad