The key is not meant to take the load of spinning the flywheel, it
is only there to make correct alignment. Clean the inside of the
flywheel taper and the outside of the spindle lightly with fine
sandpaper or some such. You can even add a bit of talc, rosin,
or soap stone to the taper to help it seat. Make sure you have
the correct flywheel key. Make sure you set the flywheel back on
the spindle with it's nut so the taper can take the load. You
should reset the magneto while you have the shroud off. A
business card works about right.

___________________________
Keep the whole world singing. . . .
DanG


wrote in message
ups.com...
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.