A friernd has a Jonsared 535 chainsaw. I believe the flywheel key is sheared due to the fact that it takes a 600 lb gorilla standing on the saw to pull it over. Since I do almost nothing for repairs on the small 2 cycle engines, due to my fat fingers not being able to get into the cramped space, just wondering waht would cause the key to shear on a chainsaw. When the chain gets stuck while sawing, should the clutch kick out before shearing the key?

 

i have an old 'craftsman' 20" saw, that you can't pull through - without using the compression release feature.
does this thing have such?

 

no compresion release on this 1.

 

If the clutch is fully engaged and the saw comes to a sudden halt, the key can definitely shear.

 

Indy,, I beleive the key is part of the flywheel on these.. Pull it apart & take a look... If it's O.K,, Then I'd be thinking the ignition coil has gone bad,, & the reason I'm saying that is we had 1/2 dozen Stihl weed trimmers that acted as the key broke.. All was fine on inspection but the coil fixed them up,, I think something went wrong in the spark advance part of them.....Roger