I have a 40 year old Dayton/Briggs 3500W generator that only gets cranked when needed... often years between use. One time it sat so long I had to hook a 12V battery to the output to re-magnetize it before it would work. Much the same for a 400 amp portable welder that sit outside in the rain and it was not new 40 years ago when I bought it.
If you cannot shut the fuel off to your generator and run the carb dry, then running it to get fresh fuel is all I would do. I only crank the diesel generator in my MH when I need it.