Small Engines (Lawn Mowers, etc.): 18.5 hp Briggs and Stratton, huskee mower, briggs and stratton

Question
Hi - I have a 18.5 B&S - Huskee mower.  When I was cutting grass it all of a sudden starting dying.  When the PTO is turned off it will run fine.  But, when engaged the mower will start stalling/dying.  Any ideas?  The belts look good and turn, will go into gear and run for about 5 seconds and then start stalling.  No grass build up.  I'd appreciate any suggestions.
Thanks

Answer
 Hello Kevin:

 Does it Do this Only when the Engine is Hot? If it Does it Even with the Engine Cool, then it May be that the Carburator needs to be Cleaned and Rebuilt. If it is Doing it Only when the Engine Heats up, then it May be the Valve Clearance needs to be Reset. Im Thinking Carburator First. From your Description, the Main Jet of the Carburator has Trash/Water in it. Hope this Helps. Let me know what Happens, Please. Thanks.

 Good Luck

 Respectfully

 John