Many variations of the original pin drive 277095 prop used on your motor were also used on later 30, 35, and possibly 40 horse motors so locating a good used one shouldn’t be too hard.
Here’s a parts manual for a ’55 Evinrude Big Twin Electric which should mostly be the same as your RD-17 except for cosmetics and the electrical system. Evinrude and Johnson were just starting to share parts around this time so I can’t guarantee it will be identical.
