Small Engines (Lawn Mowers, etc.): craftsman/honda, craftsman model, fuel stabilizer

Question
I own a 2005 craftsman model # 917.273500 with a Honda 16.5 hp engine.  It developed a non-starting issue that has gotten worse over time.  It will either start right up or have no hope of starting.  I replaced the solenoid on the carburetor because I thought this was the problem to no avail.  I next checked to see if it was getting spark.  The strange thing here is that it appeared there was no spark at the plugs (with the plugs removed and grounded) however by sticking a screwdriver in the plug wire and bringing it near a ground I had spark.  I did this repeatedly (no spark at the spark plug but spark with a screwdriver inserted to plug wire near ground. I installed new plugs and have them gapped to proper specks.  Also the engine is getting gas so that is not an issue.  Why will it stat right up at times and then not start the next?

Answer
Do you use fuel additives?  I have found some Honda engines where the intake valve will sometimes stick causing your problem.  The Honda engines use very tight tolerances and just a small amount of stale or lower grade fuel can cause the valve to stick.

I had another one with a carb issue.  Ended up having to replace the carb because it would start sometimes and not start other times.  

The next time is refuses to start try sparying some starting fluid directly in the carb.  If it does not start, check for spark.  Check to see if the plug is wet or dry.  If dry, spray starting fluid directly in the spark plug hole and see it starts.  Basically trying to rule out fuel and spark.  

In the mean time, start using fuel stabilizer and fuel conditioner/cleaner to make sure the intake valve is not sticking.

Let me know what you find.  Be patient as this is the most frustrating problem I've found with Honda engines.
Eric