Mercury Mariner 200, 225 Optimax Outboards Service Manual, 90-855348, Page 236Get this manual
Cleaning and Inspection Cylinder Block and Crankcase Cover
IMPORTANT: Crankcase cover and cylinder block are matched, line-bored assembly and never should be mismatched by using different crankcase cover or cylinder block
Special Service Information
Grooves in Cylinder Block Caused By Crankshaft Sealing Rings