1997 honda 15 hp stalls out after a few minutes

[stovebolt62]

Guys, just bought a used 1997 Honda 15 HP outboard, seemed to run fine when checking it out, but when I got it home, it will only run for a short time, then stall. I have only run it in a test tank. It has a brand new carburetor, the float is good. It will run for awhile, the bulb gets hard when priming and seems to stay that way. When it starts to run out of gas, I pump the bulb and it seems to help keep it running, choking it also seems to help. I can see the fuel level go down in the fuel filter as it's running. Can I assume this is a bad fuel pump? The carb is brand new and clean as a whistle and I don't see any fuel lines leaking. I haven't had much experience with four strokes, is there a way to test the fuel pump to see if it is bad? Thanks for any help.