Small Engines (Lawn Mowers, etc.): B&S 31C707-0230-E1 Timing, crank shaft, cam shaft

Question
I have rebuilt this engine and am having a bit of trouble with the timing.  I have taken it apart twice today alone and re-adjusted to no avail.  To my understanding there is a timing mark on the crank shaft gear and one on the cam shaft gear.  I lined them up to be together put the engine back together it cranks over and back fires but does not run.  I took it apart again and readjusted.  Second time I adjusted it so that the piston was on its trip UP the cylinder and just passed the magnet and put the timing mark so that it would line up with the one on the cam shaft gear.  The one on the crank gear is directly on a tooth and the one on the cam shaft is between two teeth.  I made it mesh together where the dots are exactly in the same spot.  This time the engine fired a little better but still back fires, flames shoot out of the intake and a lot of smoke from the intake as well.  I am at a loss with this and can not figure it out.  Also there is a plastic gear inside the engine that controls the speed control or governor what ever you want to call it.  Does this have a specific position it must be in as well?  Is there a guide somewhere I am missing with detailed explanations and illustrations or what can I do to help remedy this?

Answer
Roger
Did you check the valve clearance at top-dead-center on the compression stroke?  What are the valve clearances?When you check the clearances on the valves you need to bring the piston up to T D C and a notch past that. That will set the valves in the correct position.Here is the Illustrated manual and parts numbers for your engine.

http://www.briggsandstratton.com/maint_repair/manual_and_more/docsearch.aspx?mod...


I trust this will assist you  in making the correct replacement
Also your timing is out of correct firing order .
Easy way to set timing is this way.
1. with the magneto flywheel at After magnet Both Valves should open slightly together
2. As the Flywheel turns intake opens fully and exhaust is closed as the piston begins to travel up the intake closes and compression begins with firing as the magneto is at Top Center.
3. As the Magneto passes and the piston begins to travel down the exhaust valve should open as the piston comes back up both valves open again.