HI Art,

My first suspicion would be a broken flywheel key. I have the same
engine in a Craftsman lawnmower and the damn thing breaks about two keys
per season.

The key is an aluminum/pot metal sorry excuse, all you need to do is hit
a rock, tree root etc, and it will partially shear, ergo engine timing
is out.

There is no easy way to check short of pulling the top sheet metal,
remove the recoil mechanism, remove flywheel nut and check alignment of
flywheel to crankshaft. If not dead on, this may be your problem.
WARNING, do not attempt to pry flywheel off, it will break, replacement
worth more than mower! Use puller, apply heat to flywheel at crankshaft
and the apply pressure. Fly wheel is mounted on taper.

Dave

Art Renkes wrote:
I have a Scott SP walk-behind mower with a 6.5 HP Tecumseh motor. The
last time I used it (about 2 months ago) it seemed to run fine. Now it
apparently makes no attempt to start (after priming it and after many
pulls). In addition to this problem, while trying to start it the
engine sometimes jerks the starting rope out of my hand (backfires?).
Can anyone suggest what might be causing this and what to do about it?
Thanks for any help.
Art
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