it will run a little leaner in the cold.. rich in the summer. after you start it up.. have a helper stand in front of the horizontal stab and run the engine up to full throttle.. let it run for a few seconds. then adjust the high speed needle (main needle) a little lean (clockwise) untill you get top rpm out of it.. then richen it up untill the rpms fall off just a bit.. (prob 1/8th of a turn) then you should be good to go.