I screwed up a couple of things below... my corrections are in brackets [ ] .

(Curtis CCR) wrote in message

Chevron claims that most [gasolines] can be stored for up to a year. They
further say that federal and California reforulated gasolines will
hold up better than conventional gas.

For long term storage they recommend -

-[Store] in areas where the temperature will stay below 80F most
of the time.
-Fill containers to 95% full to reduce exposure to water vapor and
condensation.
-Cap containers tightly.
-For long term winter storage in inboard boats, seal the tank vent if
possible.

Adding oil does not change stability. Two-stroke premix will store
the same as gasoline alone.