install flywheel key

fisheymikey · Aug 11, 2013

guys I must be an idot or something but I cant seem to get this right...

do I install it from on top or install the key then put the flywheel

pls help I already sheared one

mike

pnwboat · Aug 11, 2013

Re: install flywheel key

Install the key in the slot on the crankshaft snout first, then carefully lower the flywheel on. If you keep shearing flywheel keys, it's usually because the flywheel nut is not torqued down to the right specs (125HP = 90 ft lbs), or the slot in the flywheel or crank shaft snout is damaged.

fisheymikey · Aug 11, 2013

Re: install flywheel key

I did that the first time at 90 lbs and sheared... is too much not good either?

snout and flywheel is good

mike

scottmm73 · Aug 11, 2013

Re: install flywheel key

Ensure the flywheel key is placed so that the round part is towards the crankshaft and the flat of the flywheel key is parallel with an imaginary center-line of the crank.

fisheymikey · Aug 11, 2013

Re: install flywheel key

I know now what happened... when the mechanic removed the flywheel (I did not have a puller) and whaking the snout the nut was there and the lock nut did not work and loosen!!

can I just add lock tight or get a new nut?

thx

mike

pnwboat · Aug 11, 2013

Re: install flywheel key

Locktite should be fine. I use the red Locktite.

wickware · Aug 11, 2013

Re: install flywheel key

Will a backfire or kickback from bad timing etc cause a key to shear? Proper torque and no damages are the key factors IMO. Is there a need to lap the flywheel and crank to get a snug fit? Locktite use due to Whacking vs a new nut??? I hope the crank?s threads are stronger than nuts. That caused me to replace my nut from a concern.

I have a baby 1970 35hp Chrysler with less torque and stress but had what appeared to be a worn flywheel nut that I replaced.

fisheymikey · Aug 11, 2013

Re: install flywheel key

well installed properly the key and flywheel tapped the key from the top to make sure and it does not move..

I applied red locktight and installed the nut with a impact wrench to make sure that puppy wont move.

there wont be anymore tension on that key... don't what to be on the water and that shears again

thx for the help keep you posted

jerryjerry05 · Aug 12, 2013

Re: install flywheel key

A backfire will cause a key to shear.
Just tuning it off can cause it to shear???
Had just bought my boat. Went fishing and while out turned motors off.
Going back in only 1 motor would start.
It didn't cough or anything.
I'm going crazy looking for a reason why my NEW motor would'nt start???
My boss suggested looking at the flywheel key??
That was my problem.
Tourqe and taper can make a difference.
Adding glue or Locktite can make it harder to remove.

fisheymikey · Aug 12, 2013

Re: install flywheel key

jerryjerry05 said:
A backfire will cause a key to shear.
Just tuning it off can cause it to shear???
Had just bought my boat. Went fishing and while out turned motors off.
Going back in only 1 motor would start.
It didn't cough or anything.
I'm going crazy looking for a reason why my NEW motor would'nt start???
My boss suggested looking at the flywheel key??
That was my problem.
Tourqe and taper can make a difference.
Adding glue or Locktite can make it harder to remove.

taper?

foodfisher · Aug 12, 2013

Re: install flywheel key

The shaft and flywheel hole are tapered. Pressure from the nut forces the faces together to hold the flywheel in place with friction. The key is mainly to position the wheel for timing.

install flywheel key

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