On Jun 8, 5:23 pm, "jacko" wrote:
I recently inherited a lawn mower with a 3.5 Tecumseh 4 stroke. I tried to
start it and it kicked back hard. First time it busted the pull cord. Second
time it nearly pulled my finger off.
I was sure that the flywheel key was sheared off and the timing was off, but
I checked that and that's not it. I reset the air gap on the coil and still
the same.
I did get it to start a couple of times and it runs great . Shut it off and
try to restart and the dam thing kicks back and yanks the pull cord out of
my hand violently.
Any suggestions?

It does sound out-of-time (sheared key). As I recall...different
models have their own color-coded flywheel key. Could this have the
wrong key for that model?
Also, with the light-weight flywheels...it is important to have the
blade tight (and some blade adapters can shear)