holstein13, for whatever it's worth, last year I had the same problem with fuel pump hammering on our generator and hard to start.
In my case it was cracks in the fuel line with pump sucking air. It finally got to the point to where I couldn't start the generator as it wasn't getting fuel from the tank.
Went to the Ford shop where they dropped my tank and installed a new fuel line and now it works just fine.
Not sure that's your problem, but just a possibility, I carry a spare electric fuel pump for my generator just in case it fails.
Good luck and let us know the fix....