And the folks at Briggs&Stratten have this to say:


"It is also recommended that fuel is purchased in quantities that can be
used within 30 days. This will assure fuel freshness and volatility
tailored to the season.

NOTE: We DO NOT recommend the use of gasoline which contains alcohol,
such as gasohol. Gasoline used MUST NOT contain more than 10 percent
Ethanol and MUST be removed from the engine during storage if it is not
already treated with our Fuel Stabilizer. DO NOT use gasoline containing
Methanol. DO NOT use E85."

http://www.briggsandstratton.com/eng...nleaded%20gas/

or

http://preview.tinyurl.com/3zjvlsn