When I bought my Stihl blowers and saws, they offered to double the warranty if I bought 4 cans of their Moto-Mix, which is a 50:1 non-ethanol gasoline. I must say the equipment starts and runs well after very long non-use periods. Yes its very expensive, but when I need a saw I need it NOW not when I can finally get it started. I've seen a slightly cheaper version of this fuel at Home Depot under another name. What I wound up doing was to add my regular 50:1 gas/oil mix to the Moto-Mix to top off the cans as I used them up.