For some reason, the carburetor is running WAY rich. That can be caused by a too-high float level, a stuck power valve, or a warped top housing that creates a vacuum leak that causes the power piston to stay in the full rich position. There are some very well written instructions on how to diagnose and repair a warped top cover on the forum.
Jerry

"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!
There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway
Love your enemies and drive 'em nuts!