2001 Mercury Mariner 50-60HP Factory Service Manual, Page 265Get this manual
CYLINDER BLOCKCRANKCASE
Checking Main Bearing Clearance
IMPORTANT: Do not interchange the main bearingsReinstall in their original position1Clean all the old sealing material from the split line on the crankcase cover and cylinder block2Clean all the oil from the following areas: Main bearing surfaces on the cylinder block and crankcase coverMain bearingsCrankshaft bearing surfaces