When cold, you should always push petal to floor and back (a quick snap is all it needs) for choke to reset. On any carbureted car, one should make a practice doing so each and every time you get behind the wheel.
The reset could slam the parts into place but many times it simply pops into place (not a lot of force behind it, but some).
If the air cleaner was off, after choke reset and the cold engine is off, you should be able to push the choke plate (the top moving plate) open to look inside of it, but it will pop closed right back.
Red arrow.
Once engine is started, the choke plate may be still in a closed position, but generally is in a mid-position (not open fully but not closed) and will slowly open fully as engine warms.
That is not to be confused with the fast idle cam. The choke pulls on that cam via linkage, but that cam won’t move until throttle is touched.
It has been my experience, as the choke thermostat coil (the bi-metallic spring) gets older (10-15 years old), it doesn’t move as much as it once did (kinda falls into, and is stuck, in a mid-position). Generally 85% of the time, replacing the Choke thermostat coil (or assembly) will fix most drivability problems.
On that year, there should be a choke heater wire coming from the choke thermostat going to a white 1 inch x 2 inch electric relay (about mid position between choke thermostat and distributor). If that wire is broken off or is not plugged into that white box – that could also be a problem. The white box needs to be plugged in (goes to ignition coil, indirectly, I think).
Often, I find a broken wires) or that white box simply not plugged in.
Note: a few cars have a small round black disk, instead of a flat white box with two plugins on it.
Also make sure that white box/black disk is getting power when engine is on.
If cold drivability still exists, the one needs to remove carburetor from car, and perform all of the adjustments –
to the letter. Some of those have twenty different adjustments to it.
How well a carburetor works depends on each and every one of those adjustments to be spot on.
Need to check vacuum lines for routing and if hoses are cracked or not.
Check the air heater stove for operation (on left exhaust manifold with black or silver flex tube going
To air cleaner. I haven’t found a bad vacuum motor yet, but the temp sensor on air cleaner base and vacuum hoses I’ve seen hooked up (or not) in error or failed/broken.
Last thing is I would check the base gasket between the Thermoquad and intake. It should be roughly ¼” thick. If one is using a thin gasket or a much thicker gasket, then choke thermostat won’t work very well (already way out of specs).
If you check all of that and still have problems, write back,
BudW