On Tue, 13 Jul 2010 21:27:05 -0500, jim "sjedgingN0Sp"@m@mwt,net
wrote:

I have an old mower which might have the same problem.

You don't have to take the flywheel off to determine if the key is
sheared. Just remove the retaining nut and look at the key. If it isn't
sheared no need to take off the flywheel.

No but looking at the shear key under the nut will not tell you if the
key fractured midway in the crank key way.

Some keys don't snap or look obvious. The engine will misfire.