I bought the generator brand spanking new in early January. The counter guy filled the tank and was supposed to have test run the unit.
I brought it home and a few weeks later started it up and ran it for between 5 and 10 minutes.
As suggested by the salesman, I planned to remove the 2 month old gas this month and put fresh hi test in and run the unit for a bit. The guy recommended I do this every two months.