Craftsman Briggs & Stratton 6.0hp shakes after starting

[mmanter]

Well,

I finally got a carb for the B&S powered 6hp craftsman I got in exchange for a yardmachines I sold last year, thanks to a parts mower I bought today. Only thing, when it runs the mower shakes quite a lot.

Now, I'm pretty sure I know the answer to this but not 100% sure of the diagnosis. I'm THINKING the mower has a slightly bent crankshaft but not entirely sure. What is the best way to check this? I've rotated the crank by hand and can't really see any deflection but unsure. If it is I'd rather try and invest my time & effort in the parts mower's engine, and see if I can get it running. only thing is I'm not completely sure it will be salvagable yet, as I've yet to check into it.

Thanks for any info!

 

[Rivets]

Remove spark plug and tip the mower on it's side, carb up. Have someone pull the starter rope while you watch the crankshaft. If the blade is bent, it will also cause the unit to vibrate.

 

[mmanter]

Remove spark plug and tip the mower on it's side, carb up. Have someone pull the starter rope while you watch the crankshaft. If the blade is bent, it will also cause the unit to vibrate.

Thanks, I'll give that a try

 

[mmanter]

Found out the crankshaft was in fact bent. I removed the blade that was definitely bent, and the mounting tabs on the bracket were sheared off. Further investigation also showed the crank is bent.

 

[shiftsuper175607]

Found out the crankshaft was in fact bent. I removed the blade that was definitely bent, and the mounting tabs on the bracket were sheared off. Further investigation also showed the crank is bent.

My friend straightened his a few days ago by hitting it with a 4 LB sledge.
I think he marked the shaft then hit it...then he checked it...about 4 tries did it for him.

You have to protect the shaft with the blade adapter.

Are you sure it is bent and not just a damaged, out of balance blade?

 

[mmanter]

My friend straightened his a few days ago by hitting it with a 4 LB sledge.
I think he marked the shaft then hit it...then he checked it...about 4 tries did it for him.

You have to protect the shaft with the blade adapter.

Are you sure it is bent and not just a damaged, out of balance blade?

Yes, because the blade was off the crank. the blade itself was damaged but my Dad told me his coworker picked it up from his neighbor across the street as a non-running mower. Found out the carb was junk, air filter housing wouldn't seal for the primer button, and after swapping the carb from what I thought was a junk engine, found out the engine shook badly. Since I had a parts mower with an engine previously thought to have a bad flywheel key I put that engine on the deck, installed the carburetor with new fuel line, installed a new spark plug and it roared to life. What was diagnosed as a bad flywheel key turned out to be misdiagnosed. The mower is now running with a different engine. IF I could get the blade adapter off I MIGHT repair the crankshaft but more than likely I won't.