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Craftsman 21" Any help??

WJW Lawn

LawnSite Bronze Member
Had a buddy send me this email...anyone on here think they have a clue??

The mower is craftsman. The engine is
briggs and stratton 125k02-0477

I used the mower once this season. Then I changed the
blade.I think I did not tighten it enough. The next
time I started the mower it started vibrating and then
I have had a problem ever since. I have replaced the
spark plug and the blade adapter as well. Also, the
blade adapter shears quickly.

If you guys have any clue...let me know!!?


LawnSite Fanatic
He needs to check the flywheel key, Sounds like it's partly sheared and out of time.
WJW Lawn

WJW Lawn

LawnSite Bronze Member
Is that a tough fix for a do it yourselfer?

Bill Kapaun

LawnSite Senior Member
Albany, Orygun
"Is that a tough fix for a do it yourselfer?"
Well, we know how well he changes blades:)

"Also, the blade adapter shears quickly."

Try to get the Sears#. it'll probably be something like 917.xxxxx
Then, one can go to the Sears website and probably get an "exploded" diagram of the mower in question.
That way we can see if it has a BBC or ??

My guess (without really having enough info) is that when he ran it, it loosened up enough on the blade mount "system" , that the keyway on the end of the crank is now messed up. That may allow the blade to loosen up, no matter how tight he gets the bolts.
Like I said, we really need the mower#.


LawnSite Fanatic
Naaa, Just remove the flywheel cover then the flywheel. But use some type of puller to pop the flywheel loose, Do not pry and smack the crank with a hammer. A automotive steering wheel puller will work fine, Some auto parts stores have loaner tools.