Small Engines (Lawn Mowers, etc.): Craftsman 19.5 hp 2002 Lawn tractor Briggs straton engine, briggs straton engine, speed jet

Question
I have completed by seasonal cleaning and maintenance filter spark plugs oil lube and checked carberator to see if it needed adjustment. According to the documentation that is checked upon lowering idle speed to lowest setting and if it does not die the idle speed is correct.  The problem is it acts like the engine is choking (highest engine speed), it is very sluggish and you can hear the engine struggling w/or without blades engaged.  It still runs but it is very frustrating.  It is three years old. Does this sound like bad gas, or spark plug?  Trying to get some ideas before investing a lot of money and time.  Appreciate any suggestions.

Answer
Hi Jim,

You could try fresh gas and another set of spark plugs.  I would try adjusting the carb's high speed jet.  If still no better, try squirting fuel into the carb while running.  An improvement there, would indicate a lack of fuel flow to the engine.  

Let me know what you find.
Michael