I warm up my two and four cycle engines for about 30 seconds at about 1/3
throttle with the glow heater still on. Then I'll run the engine up to full throttle
and remove the heat, then let it run for about 20 seconds WOT and get a
main needle adjustment. Usually I can tell how the mixture is set by the sound,
but on performance engines I always adjust to lean, and set to the richer flight
setting....just to make sure the mixture isn't too lean from the start, and the
mixture is set so that leaning and overheating wont occur in flight.

Where I fly, the atmospheric conditions can change radically from day to day,
and a quarter turn on the main may be needed....thus the extra care taken at
the start of the day. One day we experienced a 1/2 turn needle adjust needed
in an hour and a halfs time.....yes, a half turn....that's about 15 clicks. [X(]

Dave.