Logo
FULL SITE MENU

mid 80's johnson 28hp spl shearing fly wheel keys

B

buddy61

New member
flywheel was taken off why i dont know, but, the key was broke so i got another $12 omc key and ran it for an hour in a barrel, purred, next day it wouldnt start and then i noticed the key was sheared off again, torqued flywheel nut to 100-105, it dosent buck or run bad when it dose run. why would it shear the key?
thanks for any input
 
i have wire brushed both shaft and fly wheel, even set flywheel on without the key, looks like theres maybe .100 between the top of the flywheel and the landing on the shaft, is there maybe a pic of some flywheel with the nut off and not popped off the shaft?
 
i thought about useing thread lock on the shaft and key, let it set for a day, never had this happen with any flywheel i removed
 
Do not wire brush anything. Use valve grinding compound on the flywheel and shaft and spin the flywheel around the shaft. Take the key out of the shaft when you do that. It could also be because somebody put the flywheel on with an impact gun. That will spread the taper and it will never hold tight. Thread lock will do nothing and make the situation worse,
 
Excellent advice. Is there a washer used on that model? As you use Mr. Scott's proceedure, remove the flywheel and observe the abrasion points. This will give you a clue of what happened.
 
Last edited:
As per "flyingscott's" reply, in not so many words.... wire brushing does nothing. The tapers must be reworked and perfect, otherwise all you're torquing are the high bumps. Besides the lapping process with valve grinding compound, depending on the taper damage... you may need to carefully do some filing (Been there, done that).

Hopefully when you stated the torque to 100-105... you meant in foot pounds.

The key must be installed perfectly straight with the engine (vertical), not aligned with the crankshaft taper.
CS-FW_Key_Align.jpg
 
Last edited:
Back
Top