"ProdigySBC_SUX" wrote in message
om...
So I Tore into the engine looking for this pin somewhere on the shaft and
yea verily, I think I found it. There is a groove axially cut into the
crank shaft (? axle?) of this engine and the coil/timing flywheel appears
to be mashed down on this shaft. The flywheel also has a groove cut into
it
to accommodate part of this square metal pin.
The flywheel appears to have been 'wrenched' a bit and attempted to shear
that pin. Hence to two grooves of the flywheel and the grankshaft are not
exactly aligned and are off about 1/4 - 1/5 of the width of that groove -
easily somewhere between 5-10 degrees I imagine. Soooooo it looks like I
need to borrow a pulley-puller and pull that flywheel to get at that pin
to
replace it.
From what i have picked up about that pin, however, I am a bit confused.
I
thought I had learned somewhere that the purpose of that pin was to allow
the engine crank to be able to (at least partially) disengage from the
axle
of the blade in case the blade hit something very substantial and whose
sudden change in rotation could damage the internals of the engine. Maybe
this pin goes farther in/along the shaft and does something I am unaware
of
but right now, the ignition flywheel appears to be out of alignment and
that
could be a big problem.
That is indeed the purpose of the shear pin but it also is critical in
timing. Even being "'wrenched' a bit" will disturb the timing. The
flywheel must be pulled and a new pin inserted. You most likely will need a
puller to get the head off.
scroll down to Timing section:
http://repairfaq.ece.drexel.edu/sam/lmfaq.htm
There are most likey two holes on the flywheel for the puller.
http://www.manddsmallengine.com/briggs/tools/
So, out of curiosity, are these motors 'mostly' interchangeable from mower
body to mower body? i.e., have the mfgrs standardzed on mounting hole
patterns, crankshaft depth/length, etc.? Surely not...
Yeah. Engines are available.
Northern Tool has a wide selection of new ones:
http://www.northerntool.com/