Small Engines (Lawn Mowers, etc.): extra gas in cylinder, riding lawnmower, needle valve

Question
QUESTION: I have a Murray riding lawnmower that I'm having some engine problems with.  For a couple months now, when I go to start the engine after it has sat for several days, it takes 7-10 seconds of cranking before it will turn over.  I was able to determine that some type of fluid is coming out of the exhaust during the cranking and just as it finally turns over, a big puff of white smoke comes out of the exhaust pipe.  Once it starts, the engine runs fine and will re-start within 1 second of cranking.  Yesterday, I went to use the mower and it wouldn't turn over at all...just momentary coughs when I turned the key...starter not turning.  I thought it could be the battery so I put it on a quick charge and tried again.  Same thing.  I was curious about the spark plug and pulled it.  It was very wet.  For grins, I cranked the engine with the plug out and it cranked very strongly and expelled quite a bit of gas out of the cylinder.  That is where I sit right now with this problem.  Today, I'm going to crank it again to see if more gas comes out of the cylinder and then re-install the plug to see what happens.  Any ideas on what could be causing these engine conditions?  Thanks.

ANSWER: Hi Mark
It sounds like to me that the problem is in the carb needle valve which would need replacing. Also check your crankcase. You probably have gas in the oil as well. If so be sure and drain and replace the oil before trying to start the engine. This is a common problem we come across often.

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QUESTION: Prior to pulling the plug, I had checked the oil level and it was slightly down so I brought it up to the full level.  I have been able to use the mower several times since my last post.  I have checked the oil each time prior to starting it and the level and viscosity is normal.  Fortunately, the mower has cranked, but it's now back to the 7-10 seconds of cranking before it expels the big puff of white smoke and then turns over.  Is it still likely that it's the needle valve in the carb if I'm not getting gas into the oil crankcase?  Also, since I'm not a big fan of personally messing with carbs, is there anything special I need to do to physically remove the carb to bring it to a repair shop so I don't have to haul the whole mower?  Thanks.

Answer
Hi Mark
Check one other thing first. Check the flywheel and magneto arms for oil and trash buildup. This can cause a weak spark or no spark at all which could cause fuel buildup in the cylinder. I would suggest to take the whole mower to the shop instead of just the carb. It makes it easier for the technician to diagnose.