Small Engines (Lawn Mowers, etc.): 17hp kawasaki on 48, 4 stroke engines, proper manuals

Question
QUESTION: After 10mins running mower the engine starts to loose power.  Sometimes I'll shut off PTO reduce engine speed and after few minutes engine runs fine.  Shortly there after engine boggs down again and this time after mowing at low speed, engine kicks in to full power.  I loosened fuel cap to rule out vapor lock.  Next time I cut the grass engine starts up and runs fine for 5-10mins and problem starts to occur.  There are times the engine will run smooth for 20mins later in the cutting process.

ANSWER: Hello Gary:

Send me the Model and Type Numbers Off the Engine and the Mower Model Numbers, Please. With these I can Locate the Proper Manuals and Better Assist you. Thanks.

Respectfully

John

PS: I am Allowed to Answer 10 Questions a Day. If you See I am Maxxed Out, then Try Submitting your Question at or Just After 9pm EST (US). My New Day Starts then. Thanks.

Respectfully

John

---------- FOLLOW-UP ----------

QUESTION: Hello John-  The mower is a 48" Scag model SWZU walk behind.  The engine is a Kawasaki FH500V 4 stroke air cooled V-twin.

Answer
Hello Again Gary:

Have you Checked the Fuel Pump? From your Description, it Seems to be either a Sticking Valve, the Fuel Pump or the Carburetor has Trash in it. I am Assuming you have Eleminated the Pulleys and Idlers on the Mower as being the Cause. You can View a Breakdown of the Engine at this Site Addy; http://www.buykawpower.com/kmcb2c/main.jsp and Select View Parts Catalog. Then Select 4 Stroke Engines. Then Select Page 3 and Select your Engine Model. Hope this Helps. I am Here if You Require More Assistance. Let me Know What Happens, Please. Thanks.

Good Luck

Respectfully

John