Crankshaft key

[jlgl]

HELP!!!..Big new problem....been working on flywheel to replace magnets....finally got them on..ran the boat and heard a horrible grinding sound...pulled flywheel and the crankshaft key broke off.

Why did thid happen?...can it be fixed?

Thanks

 

[Josh P]

Re: Crankshaft key

need to know what your working on, it probably broke the key because the nut was not torqued, or not torque to right spec. Does the flywheel key look replacable?

 

[jlgl]

Re: Crankshaft key

how do you tell if key is replacable?...broke off clean..working on 120hp merc. xr jet from a 1996 sea rayder.
thanks

 

[profade]

Re: Crankshaft key

The key you can replace, but you need to find out if the keyway is fine on the crank and flywheel. If it broke out a chunk on the flywheel then you will need a new one, if its on the crank well that's a bigger problem. I have seen the flywheels break out if the bolt is not torqued tight enough, the crank usually strip out and you can take a die grinder or Dremel and clean them up enough to accept a new key. I believe the torque spec is 120 ft/lbs but double check. Pictures might help solve what your next steps are.

 

[jlgl]

Re: Crankshaft key

I believe the fly wheel is OK. I found part of the key in the slot on the flywheel and removed it. The crankshaft looks OK. It seems that the key broke in half clean. Is it hard to replace, or should I dremel out the remaining key and replace with new one? The key simply can be replaced by placing it in the crankshaft slot?..or does the crankshaft have to be removed/replaced?
Thanks!!

 

[profade]

Re: Crankshaft key

Buy a new key, they are not that expensive, make sure the keyways are both clean, if part of the broke key is still in flywheel or crank then take a center punch and work it out. The new key can be put back into the crank, light tap if tight and then the flywheel goes back on and match it up to the key in the crank. Always use a torque wrench with correct torque spec for the flywheel bolt. You got lucky if this is all it is. Good luck.

 

[jlgl]

Re: Crankshaft key

thanks profade...I will do what you suggest

 

[calledinsick]

Re: Crankshaft key

I had a hard time keeping my key in the crankshaft slot while putting the flywheel on.

You can use a dab of grease on the flywheel shaft key (curved side of key) to help hold in place. Insert key in crankshaft depression first (curved side of key), then slide flywheel on/over matching key to key slot.