ORIGINAL: greedygibson
ok on closer inspection it looks as if someone has cut off some of the crank thread at some point thus now not being long enough going to try filing the prop down and see how that works out.
Do you know anyone that has a lathe? I had a shoulder nut made for one of my projects one time. Basically what you would do is ream the prop hole out bigger and make an elongated nut that will screw onto the threads yet stick past the prop. does this make sense?
I'll find it and post a pic.