Don't buy a new carburetor if you can get away with just a new choke pull-off.
I own a 1984 Buick Riviera with 105,000 miles on it. It is still a beautiful car, runs great and is lots of fun to drive. Lately, when I start it early in the morning, tons of black "gasoline smelling" smoke pour out the tail pipe. As soon as it has run for a bit, this stops and everything is fine. I stopped at a service station and asked them to look at it. The service manager removed the air cleaner cover, ran his index finger across something, and sniffed it twice. From this he determined that my carburetor was shot, needed complete rebuilding, and would cost $500. What would you have done if he had said this to you?
RAY: I would have said "I'll go home and get the money right now. Hop around on one foot until I get back."
TOM: All you need is a choke pull-off, Emily. These are the classic symptoms.
RAY: The choke pull-off is a small, vacuum operated device that "pulls the choke off" (opens the choke) once the car has started. If it's sticking or broken, the choke stays closed too long, and your mixture stays way too rich (too much gasoline and not enough air).
TOM: And the classic sign of a mixture that's too rich is black smoke pouring out the tail pipe.
RAY: So take the car to a mechanic you trust, Emily, and ask him to check the choke pull-off. If that's the problem, it'll cost you $50, not $500.
TOM: And send half of that $450 savings to my favorite charity, the Crash Test Dummies Widows and Orphans Fund, Tom Magliozzi, Treasurer.