[HotWheelsFan]

Quadrajets have several adjustments all around. Manual choke does two things mainly: It closes the butterfly at the top to allow more fuel into the engine and it also has a cam that opens the throttle blade at the bottom of the carb (just as if you were pressing down on the gas pedal), there should be an adjustment screw that contacts the cam or stepped lever that opens the throttle blade with the choke on. Sounds like this should help. It's called fast idle adjustment or choke idle speed and should be on the right side of the carb, choke cable side. You also should have a vacuum pull actuator that opens the choke a little when the engine starts. You can not run the engine with the choke fully closed. As you start the engine the choke blade needs to open up a little bit other wise you get too much fuel.

Bob