ORIGINAL: flybyjohn

.....I started the day (as all other days) and the engine ran fine, good idle great transition and good top end. .......... After about 4 - 9 minute flights, I thought the engine started to run a little lean during flight so I brought it down to richen it up but found out that the transition was very slow. From low throttle to high throttle the engine does not rev very fast. It takes about 5 – 10 seconds to reach full rpm but is smooth and not burbling.

............So I leaned the idle mixture and re-tuned and that ended up solving the problem. I ended up turning the idle mixture screw in about 3/4 to 1 full turn, which surprised me that it was that far out of tune.