Ok so i live in Kansas and its 11 degrees outside fired it up and rode for about 10 mins and then i stopped and it revved up and would not die had to choke it to kill it now when i fire it up it idles down slow again
airleak or lean jetting for those temps =
leakdon test,
readjust airscrew (turn in to richen it) to highest idle,
and jump 2-3 sizes up on main jet, in those temps.