I had the exact same experience with another KE4/Mark7 a year or so ago with a motor I got in Pottstown from someone I hadn't met before.

The KE4/Mark7s are my favorite motor and they are very easy to work on. Email me if you run into any issues.

It may be an easy tear down to remove and replace the
crankshaft OR it may involve some other issues...
a) this is my first go around with a broken crankshaft
b) rusty needle bearings are not unknown
Will know when we get there.
A great subject for a picture series as the motor appears not to have been worked on or worked over.

PS I picked up a Wizard WF4 today that appears relatively complete except for an incorrect prop from some other brand.