Hey everyone i just purchased the os 50 sx for my GP cap 580. Break in, the motor did great. But then the problems came. They last couple times i ran the motor, the glow plug seems to back itself out causing the motor to loose tune in flight or run up. I`m am using brand new OS A8 plugs tightened to snug. The motor has a bisson pitts muffler if that makes any difference. How can i fix this problem?

Thanks