Mercury Mariner 200, 225 Optimax Outboards Service Manual, 90-855348, Page 231Get this manual
Each connecting rod and end cap are matched machined set and must never be mismatched 16Using an awl, scribe identification number of connecting rod on inside of piston (1)Reassemble piston on same connecting rod
14Inspect pistons as outlined in "Cleaning and Inspection," following15Use Piston Ring Expander (91-24697) to remove piston ringsAlways install new piston rings