Hello: The reason for using aviation gas is that it has a 15 year+ shelf life while normal pump gas goes sour in less than a year with the current formulation. Also current fuels are hard on carb seals and other rubber type products. Unfortunately, I think that it is illegal to put avgas in anything other than an airplane. We use a Nascar type racing gasoline and add stabil. It can be purchased at many racing shops. We have had no problems. It is more expensive but so is rebuilding carbs and fuel pumps and boiling gas tanks.