I Know What Happened But Why?

[scatgo]

I would like to know why my flywheels woodruff key sheared. Dont want that to happen again. Anyone know why this would happen?

 

[saltchuckmatt]

Model number? Year? Horsepower?

Maybe it's a lawnmower....describe more please.

 

[racerone]

The flywheel key is only there to position the flywheel for correct timing !!----The flywheel is driven by the precision locking tapers.----The tapers must be a proper fit / match.-----The tapers must be lapped together with valve grinding compound if key shears repeatedly.-----The nut must be torqued properly.----Must be assembled clean and dry!---Yes I have seen the odd motor where someone decided to grease the tapers.----Key will shear as that is a blunder!

 

[ricinalberta]

Are there any other reasons it will shear if it is installed properly?

 

[racerone]

If you hit something solid at wide open throttle.---If motor comes to a " dynamic halt " due to broken connecting rod.-----Lower unit gears breaking / jumping in and out of gear.----Using the wrong woodruff key.----Where in Alberta ?

 

[Scott Danforth]

Post a pic of both the crank and flywheel. If the nut was not torqued properly, the flywheel may have been banging back and forth. Wallowing out the key seats and damaging the tapers

 

[scatgo]

Post a pic of both the crank and flywheel. If the nut was not torqued properly, the flywheel may have been banging back and forth. Wallowing out the key seats and damaging the tapers

its a 80is 35 hp Johnson. Would you happen to know the torque spec? And how can you keep the flywheel from spinning while trying to get to spec?

 

[scatgo]

While we are talking. Anyone every see a black epoxy type stuff on the stator?

 

[jimmbo]

Are there any other reasons it will shear if it is installed properly?

If the Flywheel Nut has been over torqued, it stretches the Taper, and that can cause Problems, including Shearing, down the road