J.
When I awoke this morning, I had come up with a few other things that can cause those symptoms:
1) the electric choke isn't functioning and keeps the carb on fast-idle. Put your hand over the choke to see if it warms up.
1a) The fuse to that circuit could be blown and the choke doesn't heat up. Check the fuse.
1b) The ground to that circuit is corroded or broken. Check the ground.
2) The fast-idle linkage is bound up somewhere and the carb stays at fast-idle regardless of the choke setting.
Good Luck!
