Small Engines (Lawn Mowers, etc.): Lawn Mower shut off after a few minutes..., hp briggs, carburator

Question
I have a Murray 6.0 hp Briggs & Straton Push Mower.  Lately, I've been having a problem with keeping it going after about a minute or two.  At first I thought about bad gas. So I replced the gas, fuel and air filter. Still having the same problem.  It just started about the last two times after mowing my not so long yard.  I am mechanically inclined so I am willing to do whatever nec., to fix my problem. Please help.

Answer
 Hello Roy:

 The Problem can be the Carburator needs to be Cleaned and Rebuilt or the Valve Lash could be Out of Adjustment. Run the Engine Until it Quits and then Check the Compression. If the Compression is Good, Then Clean the Carburator and Gas Tank and the Gas Lines. Send me the Model, Type and Code Numbers Off of the Engine and I can Locate a Breakdown/IP of the Engine and Carburator for you to View Online. Hope this Helps. I am here if you Require more Assistance. Let me know what Happens, Please. Thanks.

 Good Luck

 Respectfully

 John