I need to know how I can find out how to fet the timing just right on my mower
I have a 12.5 Briggs and stratton engine. It won't start because the timing is off. If any one can help me. Would be very much appreciated.

Thanks Linda

Ignition timing is not adjustable, the flywheel is kept in time with the magneto (coil) by a timing pin that shear. It would need to be replaced.

Don

In the case of a O.H.V. engine it could be valve adj. bent push rods or in my case a bent camshaft. I know that info. Is advanced but in my case it took a while to figure out. How did it happen? A valve keeper broke and the engine sucked a valve causing internal damage

If The Engine Has Not Been Disassembled With The Sump Pan (bottom Of Engine) Removed, Then The Only Other "timing" Setting Is The Flywheel Key. There Is No Adjustment To The Flywheel Key Timing. It Either Has The Key Inserted And Not "sheared" Or It Doesn't.
Remove The Blower Housing(top Of Engine Cover), Some Have To Have The Oil Fill Tube Removed, And The Screen Will Have To Be Removed. Then Remove The Large Bolt In The Center, And Sometimes There Will Be Two Smaller Bolts Holding The Cooling Fan. And Visually Inspect The Flywheel Key For Alignment. If It Is Sheared It Will Be Easily Seen As There Will Two Pieces Of Keys In Two Different Spots, And All Flywheels Only Have One Key Way And Key.

The overhead valve engine requires a valve adjustment occasionally, this is done by removing the valve cover, turning the engine to top dead center on the compression stroke and going past top dead center 1/4". Then with a feeler gauge you set the valve clearance to .004, you can purchase a repair manual from your nearest Briggs & Stratton dealer that instructs you step by step on how to do this, the manual is less than $20.00 and is a great investment for a doitselfer.