BTW, most of the bad designed 3 wire fuel pumps on 20 year old rigs have already been replaced with the new 4 wire design years ago.
If you're not very mechanical I would do the following. Put a can of SeaFoam into the gas. Attempt to start it 10-12 times. This is mostly to mix up the SeaFoam and to attempt to push it up to the fuel injectors. Let it sit overnight and also attempt to put a fresh charge into the battery while it's sitting.
After 24 hours attempt to start it again. For certain fuel related problems SeaFoam really is a mechanic in a can. I'm guessing your generator isn't starting because it is gummed up also.