More Generator Issues?

I just spent around $1,500 getting my generator (Onan 4000) to get it to run. Had plugged carburator thanks to Ethanol in fuel, voltage regulator and other small items. It now runs great and starts great, however,I sent camping this past weekend and started my generator to cool Motorhome about two hours prior to leaving and upon trip about the 2nd hour of trip, the generator died on the way. I tried to restart with no luck. It would crank but die just after letting go of the starter switch. Finished the travel and after a few hours, started the generator and seemed to run.

Did my camping for the weekend and ran generator all the way home of about 2 hour trip and ran entire trip and while home, I ran it another two hours without it shutting down. The first time, it ran close to 3 - 4 hours before it shut down. Now am wondering if the first time was a fluke or more to come later. I checked and it has full oil level and fuel tank was full or close to full when it died and never fueled up on trip either, so it ran on same fuel level coming home as on trip to camp spot. Just not sure what to think about direction I need to go.