[mrein3]

Here is what I do:
In the summer my truck gets more regular use so I don't do anything. All my engines have modern valves and guides and whatever else my rebuilder said I needed to do to combat unleaded gas.

What special-K is talking about - phase separation - you have to deal with constantly. My truck gets a plow installed and both tanks filled in early November every year. That gas isn't used up until the end of March. For those tanks full I measure out the correct amount of Sta-bil (read the label and use the long term storage mixture). Pour it in after you get to the gas station and pour your gas on it so it mixes good. ONLY use non-oxygenated (ethanol free) gas in this mixture. Non-oxy is more resistant to phase separation and Sta-bil claims they combat phase separation. On my truck I then make sure I run a gallon or two out of each tank so I know the stabilized gas is in all the lines and most importantly in the carb bowl.

Each state is different but I know that here in Minnesota if it doesn't say non-oxygenated, it DOES contain 10% ethanol. The non-oxy comes in premium only and costs more but a couple pennies per gallon in my opinion is way better than rebuilding a carb.

I'm no expert but after numerous free implements given to me because they don't run any more I have observed that all the bad effects occur in the carb bowl. I don't know how many Briggs-n-Scrappem carb bowls I've dropped, cleaned, clean the needle and seat, fresh plug, and I got a free running lawn mower. (Or snow blower or chain saw or weed whip or ...)

So long story short, treat the gas. Then make sure that treated gas is in your carb before you let it sit a while.

Oh and speaking of small gas engines, I only run non-oxy in ALL of them ALL the time. Three outboards - all non-oxy. Three lawn mowers - all non-oxy. Chainsaw, snowblower, powerbroom, weed whip - all non-oxy all the time. I NEVER deal with gas issues. Ever. And I'm pretty sure it is because I always fill my jerry cans with non-oxy.