Did you get an NGK plug? Ive never used the plug that came with the motor. I heard theyre junk, so i want with an ngk right off the bat. I also opened up the gap a bit. Never had any issues with it. I dont remember the gap off the top of my head, but i want to say something like .026 or .028". Im sure someone will chime in with the sweet gap. If i remember later, ill pull mine out and measure it for ya.