I am completely unfamiliar with the carburetors on this particular car but from your description and my previous experience with carburetors in general, I agree with the others on their diagnosis. What you have is a lean condition. If this carburetor has a float (I have never seen a carburetor without one), I would suggest verifying that the float level is correct. Do this after verifying proper pull off of the choke and proper operation of the acceleration pump as Larry Delor suggests. It would also be a good idea to make sure you don't have a vacuum leak. Check for the obvious: loose vacuum hoses, etc...
A SUGGESTION TO CONSIDER FOLLOWING AT YOUR OWN RISK AND DISCRETION:
I have successfully searched for vacuum leaks in the past by VERY CAREFULLY spraying a SMALL amount of carburetor cleaner around various seal areas of the carburetor and intake manifold with the engine idling. KEEP A FIRE EXTINGUISHER HANDY just in case. DO NOT USE STARTING FLUID (ether). When you hear the engine idle speed increase, you have found your leak. AGAIN, THIS IS ONLY A SUGGESTION. TRY AT YOUR OWN RISK.
Best of luck.