RE: It wants to fly backwards. Problem Solved!
Maybe it's too late to mention it now but I believe the Enya SS40 has a cast iron piston. If it's been run in like an ABC then it may be run out by now. The quality of Enya engines is superb and a cast iron piston run in properly will last so long it'll be a family heirloom IF you use the right fuel (meaning oil type and quantity).