I have a '79 210 with stock Hitachi carb. It's been a daily driver for years. I recently rebuilt the carb and cleaned the nozzles, which solved some jerky acceleration issues I was having. However, after that, I've been having issues with my cold start. Choke seems to be properly adjusted - butterfly plate fully closed and fully open when warm. However, I struggle to get the car to enter a normal high idle in a cold condition. It reluctantly fires up and chugs to life, spewing lots of rich smelling exhaust in the process. rpms are very low and it wants to die. After a minute or so, if I give it lots of gas, RPMs will go up, but nowhere near the high idle I used to get during a cold start. Then, once warm, it runs like a dream. It will re-start easily if warm and run fine.
I confirmed there's a strong spark from the ignition coil at start. Also confirmed that distributor rotor points towards plug #1 at 10 deg from TDC. I've tried adjusting the fast idle screw both ways, but it doesn't improve cold start. If I move the screw too far in either direction, it won't start at all.
Other potentially relevant information... the car was stolen last year, and when I got it back my ignition switch got pretty messed up. I am still finding other weird things that got messed up during that period... so nothing's off the table here.
Appreciate the help.