Welding a crankshaft in an aluminum engine.

JMO,, I would be inclined to carefully grind that weld or whatever off till I could pull the gear off,,

The woodruff key is half-moon shaped,, so if you tap down on one end of the key,, it "curls" the other end out of it's slot, till you can grab it with vicegrips,,.. clean up the shaft and slot, install a new key,,

PS.. If you happen to grind a little off the gear or crank,, don't worry about it,


if that doesn't work,, go back to your original idea.. lol

hope it helps