On 17 Dec 2006 10:26:56 -0800, wrote:

I have a 15 HP Craftsman riding lawn mower that uses a Briggs and
Stratton engine. Anytime I put the key in and start it, all I get is a
clicking sound. The flywheel doesn't turn at all and after a couple of
clicks, smoke starts coming out of the engine compartment. So I talked
to a guy at the Sears repair place, and he told me to change the
starter, solenoid, and flywheel key. So I buy all three and put them
in. (Note: The old flywheel key was in perfect condition) I give the
engine full throttle and turn the key. The engine suddenly comes to
life and sounds as if it had a lot more power than before. I turn the
engine off and go inside.

The next day, I try to crank up the engine, and it won't start. The
starter motor is turning the flywheel like is supposed to, but its just
not cranking up. So I change the spark plug with a brand new one and
try to crank it up again. It does nothing. I then open up the flywheel
and see that the key is sheared completely in half!!! I change the key,
close everything up, and restart the engine. It cranks up fine and runs
perfectly. But I turn it off. Let it cool down, and crank it up again,
and it won't start again. The flywheel key is again sheared in half!

So everytime I change the key, it works fine. But then the second time
I crank the engine up, the key shears. What do I do? I don't think the
crankshaft is bad because the original key that I pulled from the mower
the first time was fine.

The key may be slipping a bit when you place the flywheel on. I've
seen this happen. A tiny dab of bearing grease helped hold it in place
enough to replace the flywheel. No more shears after that. YMMV.

--
Oren

"Well, it doesn't happen all the time, but when it happens, it happens constantly."