I think it's the A-Main fuel with the hi-tech synthetic oil. I am the same. The internals in my motors when you pop off the backplate are pristene. Same deal with the plugs - take the plug out at the end of a meeting to after-run the motor, and it's like a new plug straight out of the packet. Makes more power, and the thing will sit there and idle all day - and still take off with minimal hesitation even after a couple of minutes. Using medium plugs too. O'Donnell 77T or RB #6, depends which one is cheapest at the time. Going to start running the new GO T4 medium plug soon and see how that goes.