Small Engines (Lawn Mowers, etc.): B & S 13hp Riding mower engine, starter solenoid, oil level

Question
Sir,
I have had problems with my 13HP B&S 28T707 engine.  At 1st it would run fine for about 15 min. and then stall.  I figured maybe a clogged fuel filter, bad plug, or bad gas.  Replaced them all.  Now it runs overspeed.  I have since replaced the starter, starter solenoid, battery, checked wiring and fuses.  It is electric start.  I even put the old equipment back on and it still overspeeds.  I cleaned out the carb. w/ carb. cleaner, checked the float, and replaced the air filter.  Still overspeeds. Oil level is fine and clean.  Was told by B&S that the governor could be the issue.  Can you help me to repair my problem.   Spent almost $200 on it.  Would have been cheaper to just take it to a B&S Cert. Mech..  Thought I was trying to save money.  The mower is only about 4 yrs. old.  No leaks, cracks etc.  Linkages seem fine. Can turn engine by hand.  Hope this was enough info.  Thanks for any advice.  Mr. Terry Toncic

Answer
Can you move the carburetor butterfly, the one connected to the governor linkage, by hand.  It should move with minimal effort.

Is the governor spring and the surrounding area clean?  I've seen dirt/oil/debris collect in this area preventing the governor from working?

Have you messed with the governor?  If not, DO NOT mess with it.  You can check the arm to see if it moves and check the tightness of the governor arm screw/bolt but DO NOT loosen the screw.

Let me know what you find.
Eric