Small Engines (Lawn Mowers, etc.): Honda 16.5 HP engine surges, honda, carburetor

Question
I have a Sears lawn tractor with a 16.5 Honda engine(model # GVX 530-EXA1) It just started surging when not under a load(governor cycling) It surges from fast speeds to medium slow speeds.  At idle, the engine quits. The right plug is clean, the left plug has some carbon on it.  I always use STA-BIL in the fuel.  The air filters are clean.

Answer
It is possible for the governor or even the governor spring to cause surging.  But 90% of the time it's because of a dirty carburetor and in your case, since you have one fouled plug and one clean one, I would almost bet this is your problem.

This carburetor looks fairly difficult to work with if you're not used to carburetor work.  It is a little more involved than your simple one barrel, but it's not too bad.  It's pretty forgiving actually.  I would recommend a rebuild with a new carb kit and a good soaking in a carb vat or ultrasonic cleaner.  You might have success with spray cleaner but I wouldn't recommend it.  Let me know if you have any questions.  Thanks, PK.