For 1968-78 Johnson/Evinrude 2-cyl, 40-55 Hp outboards.
Hub uses key 47-01407
ID: 16.04 mm | OD: 69.8 mm
W: 22.1 mm | 6 blades

also crosses with:
Sierra: 18-3083
GLM: 89660
Mallory: 9-45209