Mercury Mariner Outboard 225 3 Litre Service Manual 1994, Page 154Get this manual
Piston Installation 1Before installing new piston rings, check gap between
Check piston rings to be sure that they fit freely in ring grooveOutboard Oil
ring ends by placing each ring in its respective cyli nder,
then pushing ring about 12 in(12.7mm) into cylinder using piston to assure proper position
5Lubricate piston, rings and cylinder wall with 2-Cycle
Check end gap of each new piston ring with feeler gaugeEnd gap must be within 0.010 in to 0.018 in(O.2S4mm to 0.457mm) If end gap is greater, check other piston rings in cylinder bore, until rings (within tolerance) are found,
aPiston Ring Expander01 SideUp" on Piston Ring
6Rotate each piston ring so end of ring is aligned with
locating pin as shown
Install Piston Ring CompressorRemove screws and connecting rod cap from piston rod assembly being installed
IMPORTANT: Piston must be correctly installed and positioned as shown52327