Small Engines (Lawn Mowers, etc.): GX 345 white smoke from exhaust, blown head gasket, gasoline smell

Question
QUESTION: My GX 345 with a Kawasaki 20 hp liquid cooled engine runs great most of
the time but will start blowing white smoke out the exhaust for no apparent   
reason.  Each episode last approximately 1 to 2 minutes then it runs great
for hours... Sometimes it cranks and runs several minutes at full speed
with no load just warming up then starts an episode.

The smoke is really thick during these episodes.  It seems to be having
episodes more frequently. I keep the air filter clean as possible and check
all fluid levels before starting engine.

Michael

ANSWER: This sounds to me like some instances I have seen when fuel mixes with oil in the crankase and it gets overfull. When running, the vacuum in the engine causes the oil/gas mixture to be drawn into the carburetor through the breather and get burned up in the cylinder. Check the oil and see if it smells like gasoline.

---------- FOLLOW-UP ----------

QUESTION: I can't detect a gasoline smell in the crankcase or on the dipstick.  Should
I remove some oil and see if the level rises after running it or is there
another test I can do?  

Answer
When it smokes are on an incline? A couple years ago briggs had an engine that couldn't handle a slope if the muffler was in the lower position, the oil would just run out of the crankase and make clouds. The other thing this could be is a partially blown head gasket, allowing oil to go from the pushrod housing into the cylinder occasionally. The only way to check this is with a leakdown tester. You will probably need to take it to your local repair shop for this.