I had that same generator for 17 years. Easy starting and reliable. Late last year it fried some surge protectors in the house, and I found it was making 340v at the 220v plug and 170 on the 120 plugs.
I replaced the AVR without fixing the problem, and gave the generator to my electrician neighbor. In short order he found a bad connection on a wire coming from the AVR. It's back to purring like a kitten!
Holy high power Batman that's making me nervous, just the opposite of my issue. Did you get a replacement?