Hi guys! I'm a beginner R/C'er who has flown four times now. I've got a brand X trainer with a OS 40 engine. The guy that gave me the engine helped me initially start the thing and get it leaned out correctly. My first flight went great as far as the engine is concerned. It started and ran fine. My second flight was the same. Now, my last two flights I have been having problems getting the fuel/air mixture set right. Seems like I can't find that sweet spot. I was taught to find the mixture which allows the engine to run at idle and full throttle in all attitudes. Seems like it should work right? Anyhow, I've been able to apparently get the engine running right, but during my flights, it is obvious that the mixture is still not right. I love flying the plane so much that I usually keep flying despite not having full power. On one of my flights I had landed to mess with the fuel and I just got frustrated with it cause I was wasting time with it on the ground and not enjoying flight time. I ended up taking off and flying it anyhow! I am a self taught beginner in RC so I am learning as I go. I have my private pilot's license to fly the big birds, which has helped me alot in learning RC. It doesn't help me however with these small glow engines. I have tried new fuel by the way and seem to get the same results. Maybe a new Glow plug? Any help you guys can give me would be greatly appreciated! I guess I need a beginners guide to setting up your glow engine!