blue smoke indicates that the engine is burning oil, and it is probally from worn piston rings, or cylinder bore. as long as the mower still performs well this is not too much to worry about. just make sure to keep the oil at the correct level and clean the spark plug after every few hours use to stop it from oiling up too much.
most of my Suffolk mowers burn oil and they still have plenty of life in them, its nothing to worry about.
Jammin James, February 2005
