Small Engines (Lawn Mowers, etc.): Need help removing flywheel from 19.5 hp briggs motor on craftsman riding mower, craftsman riding mower, hp briggs

Question
I need to replace the starter gear on my craftsman riding mower, and it appears like I need to pull the flywheel off to get to it.

I can't figure out how to go about this though.  There's a large nut on top that it seems I need to unscrew, but I can't budge, especially since the flywheel wants to turn with it.  I can't seem to find anyway to chock the flywheel safely.  What's the trick?

The tractor is a model 917.270810,
The motor is a model 42E701, type 2631e1, code 9712185b

Answer
Hello Michael:

Air Tools or an Electric Impact is Best to Remove the Flywheel Nut. However, Remove the Spark Plug and Go to the Local Hardware or Automotive Parts Outlet. Purchase a Bolt the Same Diameter and Threads as the Plug. Make Sure it is At Least 4" Long and Threaded At Least 3". Install this and Then Turn the Engine by Hand Until the Piston Jams Against the Bolt. Remove the Flywheel Nut. Attach a Steering Wheel Puller in the Holes Provided in the Flywheel. Tighten the Puller and Then Hit the Puller Bolt with a Hammer. Repeat this Procedure Until the Flywheel Jumps Up or Loosen Enough to Lift it from the Engine. Remember the Flywheel Nut is Torqued to 150ft Pounds. Hope this Helps. I am Here if You Require More Assistance. Let Me Know What Happens, Please. Thanks.

Good Luck

Respectfully  

John