Mercury 75 Service Manual page 262

Piston rings are TAPERED top side, and flat (rectan-
gular) on the bottom side (half-keystone rings).
a - Enlarged View of Piston Ring Grooves
Care must be taken not to scratch the side sur-
faces of ring groove. Scratching this area will
damage the ring groove.
1. Install piston rings using Piston Ring Expander
Tool. Spread rings just enough to slip over piston.
2. Check piston rings to be sure they fit freely in
groove. Lubricate rings and cylinder wall with
2-cycle oil.
b
14
14 2 Cycle Outboard Oil (92-826666A24)
a - Piston Ring Expander
b - Piston Rings
4-50 - POWERHEAD
a
a
51081
3. Align piston ring end gaps with ring locating pins
as shown. Check locating pins making sure they
are tight.
a
b
a - Locating Pin
b - Piston Rings
4. Remove connecting rod cap from connecting rod
being installed.
5. Install each piston with "UP" identification facing
flywheel end. Pistons MUST be installed in this
direction.
90-830234R3 DECEMBER 1997
a
b
a
53988
UP