Small Engines (Lawn Mowers, etc.): black smoke on 23hp kaw, throttle arm, air filter

Question
black smoke under load. already cleaned carb,new plugs,clean air filter. the throttle arm on the side of carb continues to move back and forth. any ideas?      thanks jimmy

Answer
I need a model number on the engine.  I'm guessing you have an externally vented carb but an internally vented air filter.
Get back to me with the model number and I will give you the part numbers and service bullitens you need to fix this very common problem.