18.5hp Briggs shears flywheel key when starting

[ed45usa]

with the spark plug unhook, engine turns over find. hook up the spark plug, turn engine over and just as it is about to start, the flywheel key shears. any ideas anybody

 

[Scrubcadet10]

What type of equipment is it on? Engine model number?
Have you or anyone else removed the flywheel recently? The nut may not be torqued properly.

 

[StarTech]

First we need the engine Make , Model, and Spec (Type) numbers. And as I was just posting have you properly torqued the flywheel retainer. Also it does sounds you have a valve adjustment problem or camshaft ACR problem.

 

[bertsmobile1]

And check the key way on both the flywheel & the crankshaft.
They can raise a little burr when the key breaks which prevents the tapper locking in properly so no matter what you do the ket will continue to shear till the burr is removed .