Easiest is to have someone w/ an impact wrench remove it. you can feed rope into the spark plug hole and it will prevent the engine from turning. One must be careful on OHV engines.

As stated earlier you can freeze the engine and all engines by removing the spark plug and inserting starter rope into the cylinder..
On 4 cycle with OHV you will need to make sure both valves are closed. Then go ccw fron the blade side 1/2 .Turh cw and the piston will jam against the rope.
As for tightening you can put a socket on the flywheel nut and tighten the screw.
If you try to loosen it this way you may loosen the flywheel nut.
BTW is your mower a Stripping Mower?
I have one and I love it!

As stated earlier you can freeze the engine and all engines by removing the spark plug and inserting starter rope into the cylinder..
On 4 cycle with OHV you will need to make sure both valves are closed. Then go ccw fron the blade side 1/2 .Turh cw and the piston will jam against the rope.
As for tightening you can put a socket on the flywheel nut and tighten the screw.
If you try to loosen it this way you may loosen the flywheel nut.
BTW is your mower a Stripping Mower?
I have one and I love it!