The carburetor is pouring fuel into the intake. The most common cause for this is a leaking float valve, often because of a bit of grit that has caught between the needle and the seat. It can also be caused by a leaky float in the carburetor.
Back in the day I would change out of my bell-bottom corduroy pants and put on my bell-bottom blue jeans. Then I would disconnect the fuel line from the carburetor (watch out for the spray when you remove it) and plug the hose, then start the car and run it until it died from using up the gas in the float bowl. Then I would hook the fuel line back up and hope the inrush of fuel past the float valve seat fixed the problem. If not, I had to get a carburetor rebuild kit. The float is the important part, because if it fills with gas and no longer floats the symptoms you see will appear, too. That can be observed by removing the top of the carburetor, but doing that on the car is risky - springs and things occasionally pop out when the top is removed. Carburetors are best rebuilt on a bunch of newspaper. That way you can read about people with more trouble than you have.
Starting the car is not so hard with the fuel line disconnected - hold the accelerator down and crank away. If that doesn't get it going for a few seconds we are barking up the wrong tree.
35 years maintaining my own cars