I had the same problem this summer with mine. Bought a 1995 with only 38 hours on the genny. I also replaced all the same stuff. The conclusion I came to was that the carb was probably partially gummed up. When it died on me I pulled off the fuel line from the carb and sprayed some carb cleaner in it. Then I cranked over the engine a few seconds to suck the carb cleaner into the carb, then I let it sit and soak for at least 20 min and started it back up. I ended up doing this 3 or 4 times in the 2 weeks we were camping in July. Havent had any more problems with it. I should probably still remove the carb and give it a good cleaning. The only reason I didn't just remove it while camping was that due to the tight fit and positioning of everything it looked like more of a pita than I wanted to deal with while on vacation.
Bob Kulhanek 1995, 29 ft, Coachman Leprechaun, Ford E-350, EFI 460, 4.0 Onan Gen
If it won't budge, hit it harder or get a bigger hammer.