Small Engines (Lawn Mowers, etc.): Kohler cv14 runs load & rough esp. under load, simplicity lawn tractor, white smoke

Question
I have a Kohler cv14 on a simplicity lawn tractor. It started getting load and I thought I had a hole in the exhaust. I did a tune-up...air filter was very dirty, I installed a new one, spark plug was not fully seated...I installed a new one. I thought the plug was my problem, but issue remains. I changed oil and filter and tried to cut grass. The engine runs rough. If I have the break on, least load on engine, it sounds a little better. When I take break off and then engage deck, the engine gets louder and I have to go slowly to keep if from stalling out. If I disengage deck before stall-out, I get some white smoke from exhaust. I'm thinking carb and too rich a mixture, but I'm a rookie...

Answer
I would start by removing, dis-assembling and cleaning the carburetor with compressed air from an air compressor and carburetor cleaner from a spray can.

Since the spark plug was loose I would also check all the carb mounting and muffler bolts.  How old is the engine?  

THe link below is a carb video I found while searching youtube.

http://www.youtube.com/watch?v=MHPX5ihAIXY&feature=PlayList&p=A13358DCFFBEE566&p...

Let me know if the carb cleaning fixes the problem.

Eric