Small Engines (Lawn Mowers, etc.): push mower wont crank after it gets hot, briggs and stratton, hp briggs

Question
I have an old 1970 3 1/2 hp briggs and stratton classic push mower. It has a diaphram type carb.  It does not have a primer bulb carb. It cranks good when cold and runs good until it goes dead or I turn it off.  It will not start back until take the breather off and open the valve with a screwdriver. I have put on new breather and it does the same thing. What do I need to do to fix this problem?  Thanks.  Stephen Pettyjohn

Answer
Hello Stephen:

From your Description it Sounds like the Old Tank Mounted Briggs that has the Air Vane Governor Under the Blower Housing. The Carburetor has an Auto Choke Feature and these were the Best Push Mower Engine Briggs Ever Manufactured. The Problem you are Describing is Usually Caused by Low Compression or Carburetor Air Mixture Set Incorrectly. On this Model Engine, the Carburetor has a Single Air Mixture Screw. Set this Screw by Turning it All the Way in and then Reverse 1 1/2 -2 Turns Out. Start the Engine. Using your Finger, Carefully Push the Governor Arm and Rev the Engine. Turn the Air Mixture Screw in Until the Engine Starts to Stall when you Rev the Engine. Then Reverse 1/4 Turn. If the Air Mixture is Too Rich, it will Cause the Flooding you Described. Send me the Model and Type or Spec Numbers Off the Engine, Please. With these I can Locate the Proper Manual and Better Assist you. The Model Numbers May be Stamped Into the Blower Housing (metal engine cover) Above the Spark Plug. If you Hit a Snag or this Does Not Correct the Problem,  I am Here if You Require More Assistance. Hope this Helps. Let me Know What Happens, Please. May the All Mighty Bless You and Yours. Thanks.

Good Luck

Respectfully

John

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Respectfully

John