My training is going along quite well and my instructor is great, he's a very good pilot and is great at keeping me relaxed and teaching me to fly. He doesn't have a whole lot of experience at engine tuning though. I have a OS 46ax in my LT-40. After the first few break in tanks I took it out to the field and had one of the older guys with great tuning skills tune it for me. Its run good until the last 4-5 flights. (3/4 of a gallon through it now). The last few flights its been getting sluggish during the transition from idle to higher speed, especially if I throttle up too quick. Today I actually had my first deadstick. The thing that worries me is that the oil that was in the muffler today when I packed it up after the deadstick was not clear but a litle on the dark side. I packed it up at that point so I can take it out when one of the older, experienced engine guys is at the field.

I'm afraid it might have been too lean, does it sound like it may have been? What can I do next time to tell?