fuel stabilizer

I used to use Sta-Bil but have switched to Seafoam.. Several reports of issues with the first convinced me to switch.

small engines, I use AVGAS.

For my cars that will sit, Marine grade Stabil

Sea foam or Star-tron

If gasoline, start with non-ethanol fuel if possible. You can find it in most areas, but it's usually on the expensive end. www.pure-gas.org is a good resource for finding it. I'm keeping my own page for locations in Utah with a focus on how good RV access is to the station.

In the past I used StaBil. They quote a year for storage, where Sea Foam quotes two. I've used Sea Foam in my Jeep before and had good results, and switched to it for storage of gasoline. Run the engine for a while after adding whatever you do to let it get into the fuel system. Then exercise it periodically.

For long term storage I always use Sta-Bil in fuel tank of motorhome. Like you, I excerise the generator once a month as well as cranking the motorhome. Occasionally, I will take it for a short ride.

I think Seafoam does a good job. I use in my small engines.

For the Southwind, I've been using Sta-bil marine for the last few years. Works good, no problems.