Something to keep in mind with all the ethanol talk is complete opposite of something that we all grew up being told. Now, because of the ethanol fuels, it is better to stabilize the fuel and run it through the engine, keeping the tank full of stabilized fuel, than to run something out of fuel until it stops. You never actually drain a fuel system when you run something until it dies, and the fuel that remains in the system oxidizes quickly because it is now in contact with air (because you've just drawn air into the fuel system). The last time I run something for the year, snow blower, push mower, chain saw, trimmer, etc., 4 cycle or 2 cycle, the fuel is always treated with Sea Foam or Stabil, for the whole time that I am using the equipment, even if it's an hour or two. I've NEVER had a problem starting something after letting it sit for over a year, when I've done this.
A friend of mine has the exact same Lawn Boy 4-cycle push mower that I have (I sold it to him about 6 years ago), and every spring he brings it over because he cannot get it started. Finally after about the 3rd year, I asked him how he stored it, and he said, "you know, I ran it out of gas and left it because that's what you're supposed to do." I had told him specifically not to do this, but he was always taught otherwise. He still didnt' listen to me (what do I know). Last spring he brought it over, and I couldn't get it started either. Opened up the carb and it was mush.... not the fuel, the actual carb parts. Ended up costing him $100 for a new carb. On the other hand, my exact same push mower, same year, same model, actually bought at the same time, started on the 3rd pull, on the tank of old 10% ethanol gas that I left in it from last fall. I've had it for 6 years now and never even put a spark plug in it.
I do not question that ethanol is bad for things, I know that it IS. However, the things you do along with it make it worse. If fuel is treated with stabilizer, fuel with ethanol is no worse for things than regular gasoline. If you let it sit, unstabilized, exposed to air, it will go bad and corrode whatever is around it. 15% Ethanol is going to be worse than 10% ethanol for going bad and becoming corrosive, just because of the greater reactivity. Chances are, you'll never know the performance difference in whatever you're running it in, unless it's your car and you're checking the fuel mileage...... I can't imagine the complaints and discussions when the fedreal goverment finally banned Leaded Gasoline??????
1951 Farmall Cub, Cub Cadets 102, 104, 1811, 1864, Simplicity Legacy XL 4x4 Diesel with FEL, 60" mower, 50" Tiller