Okay i got the thing running and tried to fly it twice and both flamed out. didn't run it at full power long, just long enough to set the high speed and get into air, flamed out both times. then thats when i did what magnum said to do i ran a tank at half throttle, let cool, ran another tank at full, let cool, both on the rich side. I then tried to set the high speed by leaning and still getting a miss in the engine it seems, i am using a os f type plug. it does look gray and kind of carboned over now. batteries ran down about half way through trying to set the thing up on that third tank and plus we had to swap our spray plane over.