Small Engines (Lawn Mowers, etc.): Shearing Flywheel Keys, torque torque, blade type

Question
I have a Tecumseh, Model OHH60 71126C(E), Family WTPXS, 1951AB, Disp. 195, DOM 9267 K engine on a tiller.  I am getting fire and have cleaned the carb.  It tries to fire but has sheared 4 flywheel keys.  This is the first overhead engine I have worked on.  I have heard that the valves my be the problem.  Any words of wisdom would be appreciated.  Can you also explain how to adjust the valves and what the setting should be.  Many thanks.

Answer
Hello George:

Even with the OHV Engines, the Shearing of Flywheel Keys is Usually Due to Improper Torque. Torque the Flywheel Nut to 160ft Pounds. If it Shears the Key Increase to 150ft Pounds. Usually 180ft Pounds to 190ft Pounds is Enough to Stop the Shearing. The Valves are Set as Follows. Remove the Valve Cover. Set the Engine to TDC. Using a Blade Type Feeler Gauge. Set the Gap Between the Valve Stem TOP and the Rocker Arm to the Following. Intake .002in - .004in and the Exhaust .080in - .010in. Since this is a Tecumseh Engine, I have 2 PDF Site Addys that May be Helpful to You. 1- http://www.tecumsehpower.com/CustomerService/BSI.pdf and 2- http://www.cpdonline.com/692509.pdf Hope this Helps. I am here if you Require more Assistance. Let me know what Happens, Please. Thanks.

Good Luck

Respectfully

John