1986+ Mercury 6/8/9.9/10/15HP 2-stroke Factory Service Manual, Page 167Get this manual
POWERHEAD
7Remove sealing ring
CAUTION
Eye protection MUST BE worn while removing piston pin lockringsIMPORTANT: Identify upper (#1) and lower (#2) pistons and connecting rodsStore piston pin, piston pin needle bearings, locating washers, connecting rod bearings, rod caps and bolts together with corresponding piston and connecting rod for reassembly8Remove (and discard) piston pin lockrings
aSealing ringLockrings