Here I go again with a different opinion.....down goes my helpful rating, 173 at the moment.
I have a hard time buying the "Varnish" condition. Today's fuels evaporate in the carb leaving no varnish, almost no residue of any kind. This because of the detergents added for fuel injection and the 10%-15% ethonol content in all fuel.
I won't start my PC generator for a year at a time and it starts up. Yes hard to start at first, runs rough for a little while, then smooths out and all is well for the season.
The same goes for my 24 year old 18hp lawn tractor, 8 hp snow blower, and 8 hp roto-tiller. I never do any with my carbureted lawn/yard equipment when put away for the season.
Keep in-mind my off-season storage is indoors for everything except for the snow blower. That stays outside off-season in a storage shed, yet still runs perfectly fine when I wake it up.
Back to the PC generator, I can't imagine the carb going bad from lack of use. I don't know how to feel about the generator portion considering outdoor storage. That is a different subject matter.