I put a quarter turn shutoff valve in the fuel line inside the Onan and when I store it, I start the genset, shut the valve and let the engine run itself out of fuel. Fingers crossed, but so far, zero problems with the genset starting and running when I reopen that valve, prime and start the genset.
I have almost 500 hrs on it now. We live in Colorado so don't worry about moisture getting in the windings over the winter... Or actually, anytime.