Advance the ignition timing a few degrees, raise the idle speed a bit, and go about 1/4 turn CCW (rich) on the idle mixture screw. A cold engine needs a little choking to start consistently, especially as the weather gets cold. If the engine will cold start without choking it's WAAAYYYY too rich.
Jerry

"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!
There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway
Love your enemies and drive 'em nuts!