Good point. Bad fuel will ruin any motor quickly. I run Coolpower 30% Heli exclusively in my YS motors. I am sure any comparable brand, Wildcat, Powermaster and similar would be fine. Many over here use there own mix with an oil called Molsyn, a clear synthetic oil avaiable in different weights. They have good results although I do not like the smell of that oil as it burns or the way it makes the airplane smell after a while. It does not leave the motor as clean after a couple of season as the Coolpower however.

A cheap brand castor laden sport fuel will probably lessen the longevity...nothing that I have ever really tried.

Mark