Mercury Mariner V-250 V-275 Outboard Service Shop Manual 1990, Page 136Get this manual
24Use Piston Ring Expander (91-24697) and insta ll piston rings on each piston Spread rings just enough to slip over piston 25.Check piston rings to be sure that they fit freely in ring groove26Lubricate pistonrings and cylinder wa ll with light oilNOTE: Piston rings must be installed withSlopedportion facing UP L)_ _
aPisto Ring
bocating Pin
cHose Clamp (54-32533)