Small Engines (Lawn Mowers, etc.): Runs rich??, ohv motor, google search

Question
I have a 14.5 hp B&S OHV motor and it has started running badly. It seems like it won't come up to full throttle and the muffler gets cherry red. I have cleaned the carb, checked the valves but am unsure how to gap the valves if possible. the governor lever goes all the way open but the motor won't come up to speed, I believe this causes overfueling thus the red hot muffler, but I am unable to determine what might be wrong. HELP!!

Answer
Hi Alan,

Heat escaping from the exhaust valve is usually the cause of muffler overheating.  The valve may have a bad seat or may be not closing completely.  The seat should be inspected and relapped if needed.  Not closing, may be due to a weak valve spring or not enough valve stem clearance.  I forget the proper clearance.  Do a Google search to get the specs.

Let me know how you make out.
Michael