the 2100 on the 73, is a thermostatic coil, no electric feedback.
your issue seems that the choke does not close to allow proper function...
1) your thermostatic coil could be out of alignment with the cam of the choke flapper
2) there is a lever on the driver's side that is plastic and get buggered up... to adjust the opener when the engine runs
the pict below is from a new website, check the upper right side, it shows a plunger that is activated by a plastic rod
website which I have no financial gain nor real knowledge of the quality of the items being sold, for reference only,
https://www.championcarburetor.com/7274 ... 10576.html
3) the fast idle cam that can get stuck, and that seems to be your issue as well
Otherwise a note on the 2100 from personal experience:
BUT, if it is really cold, eyeball about less than 40F when the radiator takes a long time to warm up, the thermostatic coil may not open fast enough - for severe winter weather, it does not open! I made a cage to keep the choke open for winter trip in the 74.