When the choke is closed on a NH carburetor does the fuel come from the main jet or is there another source of fuel?
That choke plate when closed provides more suction from the cylinders as they rise and fall in starting. The air that is inside the air passage (A) in the carb at time of choke closing, is pulled over the puddle of fuel (G) at the spray nozzle and enriches the mixture heavily.
Fuel is sourced from the spray needle / nozzle, but is pulled by the tiny passages (D) & (E) exiting near the throttle plate.
The March-April 1925 Ford Service Bulletin has full details on overhauling the N-H carb.