I was haveing a similar problem with my P60. I got 5-10 starts on some plugs and not even one start on others...plug burned out as soon as I tried to start it. Problem for me was the glow plug votage too high. It was 2.7V (don't know how it got there...I never messed with it). I changed it to 2.1V and have not had a problem...that was about 8 flights ago.

Mike