On Sunday, June 17, 2012 3:32:36 PM UTC-4, (unknown) wrote:

What I can't understand is what pulling the cord (without starting)
does that the starter motor doesn't ?? The only difference I can see
is that the cord revs the flywheel from the top and the starter motor
revs it from the flywheel teeth below - both in the same clockwise
direction.


Not sure that's the case. When you pull very slowly, there is no resistance. You are clearly not pulling against compression. I'm not sure what the mechanism is, but some speed is required to lock up and spin the engine. Is there a centrifugal clutch, maybe?

I know that doesn't help with the diagnosis, but it might spell the difference between the rope pull and the key start.