I learned many years ago that if you put any gasoline powered engine (2 stroke or 4 stroke) away for a more than a week, ALWAYS run it till it shuts off. On my lawn tractor, I have a shutoff valve that I turn off the flow of fuel and run it to it dies. On my two Honda EU 2000s, I run them monthly with a small amount of fuel until they shut down, indicating all the fuel is used. I agree with previous comment on ethanol laced gas, it's PITA. In all my small (carbuerated) engines, and even my Mustang that I don't drive regularly, I only use 100% pur gasoline.