Small Engines (Lawn Mowers, etc.): John Deere 160 - No start, john deere 160, plug gap

Question
...following on a question from someone else to John, 2 years ago... my engine is a 12.5 HP Kawasaki.  I have had the tractor for about 6 years.  Every year this gets worse.  I have a very hard time getting it started.  Most of the time, I can use starting fluid and it will finally ignite.  I have not used it all year, with only starting it once this season.  It is about 50*F here now, and I cannot get it to fire at all.  When checking the spark, there is very little spark there at all, and sometimes none.  I seem to be getting plenty of fuel.  I have set the gap on the coil to .020 and the plug gap to .028 ( I've read .025 and .030).  I tried grounding the plug with a wire to the block and nothing.  I pulled the small wire (grounding wire) to the coil, and nothing.  When I put the small wire back, it gets some spark, but not much there.  Try to start it again, nothing.  I am leaning toward the coil.  Am I going in the right direction or is there something else I should follow?  Thanks for your advice.

Answer
I think your coil is fine.  I say this because you tell me when you spray fluid into the carb you can get it to start.  So we know we have spark.

I would be leaning towards a valve job.  It sounds like you simply are not drawing enough fuel into the cylinder.  Think of it like a syringe when you are trying to pull fluid into the syringe.

Hope this helps