Had the same problem 2 years ago with my dads unit. I replaced everything, I even replaced the carb, after $800.00 in parts I took it to the repair shop. They worked on it for 2 weeks and could not find the problem, ended up being a small hole in the intake gasket and when the generator heated up the gasket would expand and it would "suck" too much air and choke out. If I would have thought or noticed this earlier would have been less than $20.00 repair. Try it! Good Luck.