On Mon, 5 Jul 2010 07:19:39 -0700, "James H."
wrote:

On Mon, 05 Jul 2010 04:53:47 -0500, FatterDumber& Happier Moe wrote:

Does it run?
No. It won't start.

When I hit the obstruction, it stopped due to mechanical force I guess but
then it started running roughly like it was unbalanced. It almost sounded
like a multi-cylinder engine running on one cylinder - but I'm pretty sure
it's only a one-cylinder engine to start with so that's just what it
sounded like. Then, after a couple of minutes, it died and won't restart.
I've tried for a week to start it.

Yep. Sounds like you ate the shear pin. This is a soft pin that holds the
flywheel onto the crank shaft. It's designed to shear and let the flywheel go
on its merry way so it doesn't bend the crank. Since the engine timing is
taken off the flywheel, the engine won't run after. When you hit the object
you probably broke the shear pin but didn't move the flywheel far enough, at
first, to keep the engine from running. However, it ran poorly because the
timing was off. After a little time unbalanced the flywheel moved further out
of place preventing it from running at all. With any luck, a $.25 shear pin
will get you back to the fun of mowing.

If not the aluminum key was probably sheared, they are supposed to do
that so the flywheel isn't damaged and it helps prevent bent crankshafts.
I see. Looking up "Lawn mower repair flywheel key replacement" I found a
video which, to my surprise, shows you have to get to that key from the
top. (I thought everything was accessed from the bottom business end of the
motor.)

If it runs the blade was bent or a small piece of the blade broke
off, the blade came loose(unlikely) the crankshaft was bent (I haven't
seen that happen in a long time).
The blade isn't loose and it doesn't look bent. It's all dinged up but I've
had it for about 3 years and those dings started three years ago as the
soil is very rocky. About every 30 seconds I hear that hard crunch of
hitting the top of a rock. By now the rocks are mostly sheared down to the
grass level so that's why I was surprised that it stopped all of a sudden
on a pretty small rock, maybe six or eight inches in diameter that was
protroding up from the ground just above grass level in a relatively benign
rounded dome.

We really need more details to help trouble shoot it. If it's running
and the blade isn't bent it's possible the blade just needs sharpening
and balancing.

I'll give you all the details you need. It's not running but I don't
"think" it's the ignition because it was directly related to hitting this
rock one too many times.

The flywheel is part of the "ignition". The magneto is on the flywheel.

I'm googling for lawn mower repair and I see a few decent videos but none
yet for the Craftsman (I'll look up the model number in my paperwork and
report that if it helps.)

Your Craftsman likely has either a Briggs or Techumseh engine. They're pretty
much all the same.

This video shows a briggs and stratten engine being repaired with just a
screwdriver and a hammer http://www.youtube.com/watch?v=vWcIiZtvbug

I'm looking for a Craftsman one as we speak.