What should be done to a gas engine to store it over the winter months when it is not in use?

Nothing

A fellow RCU member fills his crankcase with automatic tranmission fluid prior to storage. On my four cycles it will be easy as I will just unscrew the crankcase beather and inject it. My two cycles with get ATF dribbled into the transfer port and cylinder. I haven't tried it yet but will. Some guys use Marvel Mystery Oil but that's a mystery to me.

Bill

Run it every month or so. They get gunked up and/or dry when they are not run.

Gas engines bearings dont get corroded if not used, even for a long time as the sticky oil and trapped gasoline vapour protects them.
But it'd be wise to run it every month for a couple of minutes, which is more than enough for upmost protection against ring sticking.

it better start tne next time i need it when store my planes now I do baby my weed eater and lawnmower gas engines

Thanks guys

Run the carb dry and stick the engine in a plastic bag. GTG until next season. The bag is to keep the gas/exhaust odor down....