Piston ring fits:
1980 - 1988 Merc 115 (6 cyl)
1978 - 1981 Merc 140
1978 Merc 1500XS
1987 - 1989 Merc 35
1984 - 1986 Merc 35 (2 cyl)
1980 - 1983 Merc 40 (2 cyl)
1978 - 1979 Merc 402,40
1986 - 1990 Merc 50 (3 cyl)
1984 - 1990 Merc 60 (3 cyl)
1977 - 1983 Merc 70 (3 cyl)
1984 - 1986 Merc 75 (4 cyl)
1978 - 1983 Merc 800,80 (4 cyl)
1980 - 1986 Merc 90 (6 cyl)
1978 - 1979 Merc 900,90

Thermostat, 143 degrees.  Used on wide range of Mercury outboards from 7.5 - 225 HP from 1977 - present.  Also prevalently used on Mariner outboards.  See model guide for specific applications.

Merc 50, 60, 650, 70

Merc 650 (Ser.#4382057 thru 4571651)

Over Size Piston for 1977-79 Merc 700 and 1150

Aftermarket Standard Piston for 1977-79 Merc 700, 850, 900, and 1150