Hi 808_TITAN
I agree on the usual reasons for the engines to stop in theair. It is extremly rare for my engines to stop in the air. I tune ithem to always be a little rich. I get a little less power but more reliability. I frequently change ALL of the fuel lines. I always have extra glow plugs on hand. I have been flying since 1972 and have never used after running oil. It has been close to 30 years since I took one of my engines apart so I don't know if they are rusting inside. I have engines that I run about weekly that are 10 years old. All are OS 46 FX or FA. I have wanted to see more evidence of wear so that I would at least have a reason to replace them. Hope some of this can help you.