Small Engines (Lawn Mowers, etc.): smoking engine, twin cylinder, oil level

Question
OK,, I have a 2002,twin cylinder OHV Kawasaki 15hp lawn mower engine that seems to be burning some oil. It runs ok while cold, but then smokes like a banshee while idling. Smoke disipates when you rev it back up.  It runs strong at full throttle although it occasionally sputters almost out for no apparent reason and then rallys back.  I have completely siphoned off all gas, replaced the fuel filter (twice),Cleaned the fuel lines, removed and thoroughly cleaned the carb, changed the plugs and still the same. The crankcase is not overfilled. Im thinking rings or valves.  The engine is only three years old and supposedly has low hours.  Yes, I bought this "used" from a homeowner.  Any ideas or something maybe easy that i may have missed?  Thanks for your help

Answer
Hi Brian,

If the smoke is white, from oil and not black (as fuel would burn) then I would suspect rings or valves also.  Even though it shouldn't do that, being fairly new,  without an hour meter you have no way of knowing how much it was used.  Before working on the engine I would watch the oil level to confirm that it is using oil.

Good Luck,
Michael