I had a Tec on a Toro this year that the guy sucked debris (bark mulch to be exact) down into the combustion chamber felt the same way. Had an air filter on it at the time kind of deal.

Tomplum: The air filter cartrige was stuffed up completely, so i installed a new one. This before i had tried to start it. And, a new spark plug.
This man has a large landscaped lot, with large round rocks in the areas along the walks and driveways. Rocks are 4-6 inches in diameter, piled up loosely. I think he may have a groundskeeper working for him, and those folks aren't noted for taking care of anything mechanical, unless they are paid a tremendous salary, and i'm not even sure of that.
Well, guess i'll go down and put it back together, then call him and tell him the bad news! Don't want to get into an overhaul--cost more than buying a new machine, i'd think, what with parts, labor, etc.
Thanks for your reply: Rusty

Hi Rusty,

Even the best get stumped occasionally, eh?

Weird. Is this an electronic ignition? If it were a non-electronic ingintion it almost sounds like the points are way out of adjustment.

I do think your theory of the wrong flywheel makes a lot of sense too.

Best of luck

Rusty, that model number did not show up on the Toro site. I was trying to see which engine it used. I am wondering if the incorrect flywheel key was previously installed. The gold colored off set key p/n 610995 and the silver, p/n 611004 look similar but are mirror images and I think either will fit.

Some Tecs have a flat key. Did the engine appear to be recently apart? IE exceptionally clean, loose fasteners etc. Is the key intact in the blade hub? I'd say pull the head and take a look for debris or tons of carbon build up if you're getting nowhere. It would be possible that the cd in the coil is telling it to fire at the wrong time, but likely no. Does it look new? Maybe you have one to swap? Oh the joy of not having model #s left on the unit.

Entirely possible (though not typical) that when the mower tried to "eat" the object that damaged the blade, (and stopped the engine instantly) instead of shearing the flywheel key, it twisted the crankshaft (PTO end) enough to advance the ignition timing (as you described.."fiercly yanking the rope back") It only requires a slight twist to affect a few degrees change in spark timing. Because of the style of key (long & square), someone may have put in a hardened key instead of a malleable key (which shears sacrificially by design) when replacing a sheared key in the past. Just my $0.02.

Well, i called my friend who repairs lots of mowers, etc., and this is what he told me:
He has never heard or seen a Tec. engine on a mower with the key setup i described. Not saying it never happened.
The flywheel has just a narrow slot for the key. As does the crankshaft.(Flywheels on most Tec mower engines i have seen have a wide slot in them, for the gold/silver type of key. And a narrow slot in the crank.)
So, as a result of this steel fly key situation, my friend tells me that the sudden stop, of the engine rotation, and at reasonably high rpm's, the weak point is the camshaft bearing-s in the block. They can't take the pressure from the sudden stop of rotating engine parts, so they fail, and either just break the cam, or open up a crack in the block, with a resulting oil leak out the side! Which it has! And, when i picked it up to bring home to tune it up, there was a large mass of grease and grass stuck on top of the deck!
Since cleaning the entire machine, i now see oil leaking out on the deck, from the engine.
So, the owner, when i told him what the trouble seemed to be, asked me to not do any more on it, and bring it back. So, i took it back. I figured i'd never make enough out of the job to make it worth while.
Any way, maybe my dissertation might help somebody with a problem. After all, thats what we're here for, isn't it?

Yup! We all learned something new!

Thanks Rusty.