In article ,
frankdotlogullo@comcastperiodnet (Frank) says...

Oxidation is what causes gas to go bad so you are better off
not to have much air in the tank.

Gas goes bad for a lot of reasons. Sta-Bil is an antibacterial agent
that keeps goo from growing in condensate. The ubiquitous E10 gasoline
they sell nowadays separates into ethanol and gasoline, and has a
tendency not to run. It also is worse about growing goo than straight
gasoline. Volatile fractions will evaporate out of the gasoline over
time, resulting in very hard starting in cold weather. Gasoline sold in
the winter has more volatile fractions than gasoline sold in the summer.

Save your money on Sta-Bil, and just pour left over gasoline into your
car every six months.

Never store engines with gasoline in the tank. Small engine carburetors
are open to the air. Gasoline will evaporate out of the carburetor,
leaving gum deposits that will prevent the carburetor from operating.
Run the generator empty, then drain the last few drops out of the
carburetor bowl. Remove the spark plug, squirt a couple tablespoons of
light oil (3-in-1, not WD-40) into the cylinder, rotate the cylinder
several times to distribute the oil, and replace the spark plug. Bag
the exhaust and air cleaner with plastic and rubber bands to keep bugs
out of the engine. If it has run enough to build up acid in the oil,
change the oil. If you have a dry location, store it in the same
shipping container it came in. If you have damp or humid conditions,
bag the generator in plastic with 5 lbs of activated silica gel
desiccant.

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