Outdoor Power Equipment and Small Engines - Craftsman 6.5 EagerOne Mower won't start

Kicks back very hard, suspect timing but checked the flywheel and the shear pin does not appear to be broken. This was given to me with the statement that it just quit on him and he bought a new one. I think something else happened but don't know what.

Roy

Roy, did you remove the starter cup to inspect flywheel key? I would pull flywheel to be sure.

Check the blade and adapter. Problems here could also cause kick back. Pull off adapter to be sure key inside did not shear and look at the 2 knobs on the adapter to be sure one or both did not shear/partially shear. Lastly be sure blade is tightened securely when re-installed.

Agreed, I'll say you didn't actually pull the flywheel and you need to, to have a better look at the key.

Tried but could not get it off, any secret here to getting it off? Tried prybar under it and hitting the shaft but it would not move.

Roy

Rent a harmonic balancer or steering wheel puller from autozone, get a couple 1/4" bolts long enough to attatch the puller to the flywheel (into the small unthreaded holes in the flywheel) and pull it off.

Or, using a second person to assist, have one person lift up on the flywheel with hands under the flywheel and the second person whack the crankshaft with a dead blow hammer. Be sure to protect the crank threads by threading on the nut so that it is flush with the end of the threads.

I got the mower up off the floor where I could work on it easier and finally got the flywheel off and sure enough the shear key was sheared off.

Roy

And you've replaced the flywheel key and you've properly torqued the flywheel nut back down and...? Does it run well and does it not vibrate upon running due to a bent crankshaft?

Well it runs, but I next discovered the blade was loose, it was the wrong blade and due to that the blade mount hub had the pins worn about half off so back to the parts store.

The "pins" on the blade adapter rarely "wear". Most likely they are half sheared. This along with the flywheel key being sheared tell us he hit something very hard. As Puey mentioned, check the crankshaft to be sure it is not bent. You can do it by taking measurements, I usually start with pulling spark plug, and tieing the shut off bar to the handle disengaging the flywheel brake. This will allow you to spin the blade freely. You can usually see pretty quickly if the shaft is bent.