Old crabs have jets that fix the ratio when running.
The idle mix is adjustable.
Engine hot and choke wide open...
To adjust the idle mixture screws, first set the idle screw to the lowest idle you can get and the car still run. This is the screw on the linkage. The screw that prevents the throttle plate from closing fully. Now adjust the idle screws for the smoothest idle you can get. Both of these screws should start at about 1 and 1/2 turns from full in, and will probaly adjust less a 1/4 turn either way. As you adjust you will notice the engine increase in smoothness and speed. Adjust for best idle. You may need to re adjust the idle screw on the linkage again to slow the engine down some more. If the idle screw is to high, the mixture screws will appear to not work because fuel is being pulled through the cruise circuit instead of the idle circuit. The ripples in the glass of water will show how smooth the engine is running. ( a tach is best though, adjust for highest speed) After the the mixture screws are set adjust the idle screw fo the best idle, ( about 800/900 rpm) and your done.

I think this carb has a stove located on the choke heated by a tube running down to the manifold. If this plugs up the choke doesn't operate properly and doesn't open all the way. You will find the manifold hole plugged, the pipe will will be plugged, and the choke housing will be plugged. Clean em. Be sure to put the choke back it the exact same place, Make a snall mark on the plastic and the metal housing. There is a gage with marks on the housing. Just like the timing marks. Use them.

[crabs] carbs