For 1973-98 Mercury/Mariner 1-cyl, 3.9-4 Hp | 2-cyl, 6-25 Hp | 3-cyl, 90 Hp | 4-cyl, 120 Hp | 6-cyl, 90-115 Hp outboards.
ID: 0.2187″ | OD: 0.3437″ | W: 0.0625″

also crosses with:
Sierra: 18-7120
GLM: 80080, 80090
Mallory: 9-76526