For 1956-78 Johnson/Evinrude 2-cyl, 8-15 Hp outboards.
Hub uses key 47-02357
ID: 12.75 mm | OD: 38.4 mm
W: 17.8 mm | 6 blades

also crosses with:
Sierra: 18-3050
GLM: 89770
Mallory: 9-45201