For 1975-97 Mercury/Mariner 2-cyl, 35-40 Hp | 3-cyl, 50-70 Hp | 4-cyl, 40-50 Hp outboards.
ID: 2.625″ | OD: 3.0″ | W: 0.1875″

also crosses with:
Sierra: 18-7160
GLM: 83345
Mallory: 9-76545