star-tron is a good stabilizer.

the best thing you can do for your equipment if you have ethanol in your fuel is run it all the time! that's why you see such problems with small 2 stroke engines, guys put them in the garage in the fall and when they take them out in the springtime, the diaphragms in the carburetors are hard, and the fuel lines are swollen or split. most of the landscapers and other professional users don't have as many ethanol problems because they burn through fuel on a regular basis. when the units sit with E10 fuel, it breaks down and attacks rubber parts, and corrodes aluminum.

the other part of it(which i think is more serious for outboard owners) is that it burns leaner than straight gas, which can cause detonation in higher compression engines. i'd recommend using mid-grade or premium if you're having this problem. boat motors tend to have float carbs in them which are a lot less susceptible to ethanol than the diaphragm style, but they can still be corroded if they're aluminum. best thing to do besides using a stabilizer is to drain them out before letting them sit, if you have a drain screw on the bowl.