Sorry about the short post I was pretty sick yesterday, Ethanol is a problem and will be a problem for a while. Your best bet to avoid problems is to
1. Use Ethanol free fuel www.pure-gas.org
can help you find a gas station.
2. shake the gas can before you fill the trimmer.
3. Use a quality fuel mix, not the crap you buy at a box store or the ones that look like ketchup packets.
4. Use Star Tron stabilizer in your fuel if it is stored for any length of time.
5. Use premixed fuel such as SEF at the end of the season as your last tank for storing your equipment.
Ethanol does a few things to the engine
1 it dries out your carb gaskets
2 it dissolves your fuel lines and plugs your carburetor
3 it separates your gas causing your cylinder walls to scare from running to lean
4 it draws water into your gas causing your engine to be hard to start and possibly run like crap