Small Engines (Lawn Mowers, etc.): lawn mower, float bowl, dark smoke

Question
I have a craftsman 22" lawn mower that is 3 months old.  It was running fine but the last few times it would run and then stall. I would prime it and it would restart.  Now I prime it, it starts but only runs for a few seconds.  There was a little dark smoke coming out the exhaust and a few puffs of white smoke coming out by the gas tank.  What could be the problem?

Answer
Dirty carburetor.  You can try removing the float bowl nut located on the bottom of the carburetor.  Removing the float bowl nut will drain the gas from the carb.  Make sure the small hole(s) in the float bowl nut are clean.

If this does not solve the problem then you should remove, dis-assemble and clean the carb with compressed air from an air compressor.  This is the most common repair these days.

Have you ever cleaned a small engine carb?

Is the link below the repair manual for your engine?

http://www.cpdonline.com/692509.pdf

Let me know.
Eric