If you have no choice other than using Ethanol, use it. Be prepared for problems eventually. If I work on your small engine, I can immediately (immediately) tell if you are running Ethanol in it. No ifs, ands, or buts. It leaves white, crusty deposits that are unmistakable. That white stuff quickly clogs small passages in Chonda engines (and some Hondas and Briggs) enough to make them run rough, and sometimes not at all. It also erodes any rubber in your carb over time, and seems to attract water. Now, that all being said, a Yamaha product is very, very hard to mess up. It would probably run on year old gas like it had been pumped into your can fresh yesterday. Kind of like Honda (mostly), Kawasaki, Suzuki; all superior quality small engines. AND, don't let anyone tell you Stabil isn't a decent product.
On a different note, it you have old gas and want to get rid of it, put it (not if it's riddled with water) into your car. It will burn fine as long as you're not putting it into an empty tank.