Small Engines (Lawn Mowers, etc.): briggs and stratton q6.5 eng. not continuing to run, briggs and stratton, gas button

Question
I have a three to four year old sears briggs and stratton push lawnmower with a quantum 6.5 hp engine.  It began to suddenly die when mowing one week ago.  It rapidly progressed to dieing each time it was started and ran for about 15 seconds.  The mower can be started with pumping gas into the carburetor with the rubber gas button.  When the carburetor is charged with gas the mower starts and runs for 15 to 20 seconds and then progress to die.  It seems like the engine does not have enough gas without being choked.
1.)  Does this mower/engine have a gas filter?  Could it be clogged?
2.)  Is there a common place for gas flow to be restricted or clogged?
3.)  I am reluctant to start taking parts off the carburetor without a clear plan.  But it there a common site for gas restricition?
Thank you for your attention.  I am willing to take the system apart tomorrow night if I can develop an investigating plan.
Paul Palmatier

Answer
 Hello Paul:

 The Problem is the Carb. When it is Cleaned and Overhauled, All Ports and Passages Must be Blown out with Compressed Air. Varnish and Trash has Built Up inside the Carb Ports and is Restricting the Gas flow to the Jet of the Carb. Hope this Helps. Let me konw what happens, Please.

 Good Luck

 Respectfully

 John