A&P says (In connection with a Continental O200 top overhaul) the crankshaft has too much rust between engine housing and propeller (outside engine).
I'm thinking the crankshaft diameter reduction and strength reduction from rust is less than 1% and irregular distributed over the length and diameter.
The design strength of the crankshaft has likely a 50 % safety factor. So there should be no problem.
Here are the photos:
http://hc-research.com/Continental.html
What do you think?