I'm having similar problems. When we first got our rig 3 seasons ago, the generator was fine. When I primed it after a few weeks down time, the fuel pump would run at a high frequency and then slow down and stop, presumably when the carburator float shut off the needle valve to the float bowl. The generator always started within about 5 revolutions.
A year ago December, I needed an angioplasty procedure, and didn't get back to exercising the generator until April. It wouldn't start, exhibiting signs of very rich mixture. For a number of health-related reasons, I didn't get back to it until late February this year, It still has the same problem.
When we tried to get it running for this season, I still had the same very over-rich problem. I've replaced the fuel pump and both filters and have verified that the main-jet shut off solenoid is working.
I'm now leaning towards the conclusion that the float isn't floating. The prime pump sequence will run as long as I have my finger on the switch. When I try to start the generator, I get great gouts of black smoke followed by grey smoke and it quits, maybe 3 seconds run time.
The failure code is useless - it says "insufficient cranking speed" (code 32). I figure, if it fired, it was cranking fast enough. My next test is to take the float-bowl off the carb, leaving the float and its valve in place, and see if pushing the float to the "bowl full" position stops the prime. If it does, then the next step will be take the float out and see if it really floats when immersed in fuel. I suspect that it might not.
It's not a major catastrophe. At 11 years, the genny only has 50 hours on it, and we put the last 6 hours on. Almost all the generator hours are from the previous owner's and my exercising it during the off season. 50 hours in 11 years is very low utilisation. We very rarely stay at CGs where there's no mains power and we don't use both roof a/cs that often.
We'll probably head out for a few weeks towards the end of this month even if I haven't fixed it.
Frank and Eileen
No longer RVers or FR owners