he fills his five gallon gas cans to the top,on each gas can he has mark about 1 inch down.He leaves the lid off the gas can till it reaches that mark.He says the ethanol evaporates first
I think he's probably wrong. He (or you, or anyone else wanting to) can easily check it out and see. Briggs and Stratton makes an alcohol percentage-in-fuel test kit that's very inexpensive (about $5) and easy to use. Part number is 100023; any mower shop ought to be able to get one for you. A before-and-after test would tell whether he's right and the ethanol evaporates out of the blend, or he's wrong and just throwing money into the sky as the blend itself evaporates (or worse, if he's got it backwards and the gasoline evaporates out of the blend faster than the ethanol).
