I'm not convinced the super fuels are enthenol free. Google will throw up any answer . Statements from fuel companies are the only thing to rely on , unless you can test it yourself. .. which I'm told isnt hard.
I'm starting to use aspen fuel. Apparently it's pure petrol , no ethenol and the salesmen recon is ace lol. It had a very long shelf life .
My air cooled mono's do run better on it. They run completely steady when hot with none of the weakness that you can get with a hot engine.
They certainly run better on aspen. Whether or not it seeps through fibre glass , only time will tell