I have an os 46ax which i am very happy with on all fronts but i have a question about tuneing that i hope someone can help me wiith.Why does the engine have to be run leaner in the morning before work and richer in the afternoon to get the same performance and a slight smoke trail running slightly rich. Is it something to do with atmospheric pressure or relative humidity.Its not life or death i know but i was just wondering why ?????. I am going through the same start up procedure now every fly after reading another post on RCU and i have noticed it needs a couple of clicks to run sweet,if its not right after one circuit i bring it in and adjust it.