/6 starting problems

Bad accelerator pump? After running, shut down and immediately go out and look down the throat and work the throttle, looking for a good squirt of fuel from the accelerator pump. This should start IMMEDIATELY when you move the throttle

Trying this immediately after shutdown will tell you whether you have some sort of leak/ drain down problem, or whether the pump is not working

If it's the pump, could be several things. Most likely bad pump cup, but also could be a check valve gummed up/ stuck.

What year is the car?

What year is the engine / carburetor?

Do you have a factory shop manual?