Name this Carb.....

RustyRatRod said
In your 2nd picture down, disconnect the hose at the carburetor that comes off the choke pull off and attach the hose for the vacuum gauge there.

Hey … how does a choke pull of work? When doesn’t it start and what’s the sequence of events ? I am assuming it does open it immediately.
All the carb research and messing around with them I never delved into there purpose.