assuming the starting system is fine, if the choke isn't working thats your problem. all you should have to do in the cold is get in, pump the gas probably around 3 or 4 pumps, and start it. it should start and rpm's go up with the choke on. if they go over 2 grand give it one quick pump and it should bring the choke down one notch. then as it warms up the rpms go up and another pump 5 or so mins. later will bring the choke off.
i'm not sure why you have to set the choke manually. probably a linkage or something.