BTW ddgonzal now that I've read through the auto choke adjustment section of the wiki, I get why you said key off.
Mine is directly wired (no relay) so as soon as the car power comes up, the choke heater begins to run.

I'll try this tomorrow. (So cold I'm working from home so I have time to play.)
It started way faster today with:
Don't touch the gas at all
Just start cranking
Immediately starts
then just a tiny bit of gas and let it chug and sputter for a bit before it starts high idling.

My choke cover has previous owner added marks for winter and summer and he lived locally.

For some reason I always forget the carb has a float window.
Thanks!

Quickly starting needs 3 things.
1. Fuel in the carburetor. Old carbs are notorious for drying up overnight
2. Correct fuel level (float level)
3. Tightly adjusted automatic choke


Having to wait 10 minutes before it'll start is a sign of flooding

cranking a long time is not a classic sign of flooding but of a dry carburetor. Tomorrow
before you try to start it, look at the carburetor sight glass. Do you see fuel halfway up the glass? If so, it is not flooding. If the float high up (can you see bottom edge of the float)? Then it may be flooding


Before I attempt to start it:
* KEY OFF, and Pump pedal one time
* Remove air cleaner lid
Is choke 100% closed? If it's open even a little tiny bit, that is a big problem right there. Adjust it so the choke is 100% closed. This will allow it to start right off without extensive cranking even when it's very cold. See Choke Adjustment

My B210 chokes didn't have summer/winter position. They had unlabeled marks



The center mark is where it is set when assembling the carburetor, but is not usually the correctly mark -- which can only be found through adjustment

Now, if the choke IS closing 100%, while the lid is off, hold the choke open and rotate the throttle while looking down the carburetor. Is any fuel spraying? If not, it'll need some cranking to fill the fuel bowl. Or, if fuel is dribbling out even when the throttle is not moving then the float needs adjustment. See Float Level Adjustment

My usual daily driver's broken and waiting who knows how long on parts, so I'm driving the car with the Datsun engine.
It's pretty cold here right now. Today the high temp was a little below freezing. Weds the high temp is going to be like 20F/-7C. Low temp will probably be like -15C.
The car will start, but I have to crank for a VERY long time, because (it sounds like) it's flooding. Usually when it's cold I give it one push of the throttle and then crank for a short bit and it'll fire. Right now, giving it no gas at all, the moment I crank the engine it fires a little, then dies, and then it won't do anything until I step on the throttle once to give it a bit of gas in the carb, and then it almost immediately reeks of gas and eventually (presumably I'm evaporating the excess gas) it starts to kinda fire and for a while it's like half running half cranking and then it fires up.
To be fair, all the 1980s cars I had did the same thing but they definitely started faster.
Any suggestions?
This car does not have a cold start dashpot where it pulls intake from the exhaust. It's just straight out the carb (and the hood) to an air cleaner. I've adjusted the automatic choke (the engine's from a 1981 B210) to the winter position.