How to Prevent Bent Crankshafts?

[olddognewtrks]

Well, there I was, cutting my grass (weeds), and a small stump jumped up and bent my blade, my crankshaft,(old style B&S 4hp) and now I'm a bit bent out of shape. Poop! It was an inexpensive mower, but I only had about ten hours on it.
Does any one make super-soft crank "keys", or an overrun clutch for dummies like me who hit stuff?

 

[Chris142]

I sold a go cart to a guy when I was about 16. He did a burn out with it in the dirt and when the spinning wheel hit the pavement the crankshaft broke off right behind the centrifical clutch! Thing was still running too LOL.

 

[MGregoir]

Every mower I have had has a crank that has shear pins on it so if you hit a rock or something, it breaks off the pins and you just replace that part. Odd.

 

[Johnny]

"I'm a 24 year old with 30 years experience." Not until you figure out how to keep those darn stumps from jumping up.

 

[JTK]

olddog, there's really no way to protect this type of 'direct-drive' setup, shaft key or not. This is why I can't see the value in buying a super expensive push mower. One solid hit and she's bent. Chris, that go-cart story is hysterical. I could just picture the clutch falling right off. Wahhhhh...pop...CLUNK!

Joel

 

[Slick 55]

Easy, don't hit stumps. Be glad the crank bent instead of breaking and sending the blade airborn.

 

[Cujet]

Remember that even belt drive mowers bend something when they hit stumps! Most likely the stub shaft that the blade is mounted on. Heck, they can be as expensive as a cheap mower!

Sounds like you need to spend some time getting rid of the problems.

Chris