Every year I put my Coleman stuff away I always run them out of fuel and store them with the gas cap off and stuff a Kleenex in the fuel opening and I have never had a problem lighting an appliance the next year. Just something my Dad showed me years ago.
And every time I buy a Lantern/Stove at a yard sale they've got fuel in them and don't work. A cleaning and a new Generator usually fix's things.
What is it that spoils a Generator? Stale fuel? Time? Heat? Metal fatigue? Dirt? ...........
Happy Trails
Len