Originally Posted by Creative Engineering
Did you find out for sure what caused the problem...it is unlikely that the woodruff key could do that!
My concern is how the woodruff came completely out in the first place. Actually Jim, I could see it getting jammed between the gears and the lower case. There isn't much room between them and the under power the aluminum case might get broken. I just don't quite understand how the key came completely out of the keyways. There isn't enough room on the back side and the gear should have held it in on the outboard side.
Seems like I recall reading an old post where a guy found a key inside the cover on a new engine but it was an extra that had apparently been left inside during assembly from the factory. Anyone else recall that one? A loose woodruff key could potentially do a lot of damage if it got into the right place.
As for making one fit, either the file or sandpaper method will work but the file would be quicker. A flat surface would be essential if you opt for the sandpaper/emory cloth idea. A flat concrete floor or a metal surface to lay the abrasive on then rub the key on it until it fits the keyways. The file will be flat so all you need to do is keep the material removal consistent over the surface of the key so it isn't tapered but the sides parallel.