1987-1993 Mercury Mariner Outboards 70/75/80/90/100/115HP 3 and 4-cylinder Factory Service Manual, Page 151Get this manual
Connecting Rods If necessary, clean connecting rod surfaces as follows: Attach end caps to connecting rodsFollowing these directions, tighten rod cap attaching bolts to specificationsRecheck alignmentRefer to 4A-32
Cylinder Cover, Exhaust Divider Plate and Exhaust Cover
S Thoroughly clean cylinder cover and gasket surfacesS Inspect cylinder coverCheck for cracks which could cause water leakageS Replace cylinder cover as necessaryS Thoroughly clean gasket surfaces of exhaust divider plate and exhaust manifold coverS Inspect exhaust divider plate and exhaust manifold cover for grooves, cracks or distortion that could cause leakageReplace parts as necessary
CAUTION
Crocus cloth MUST BE USED to clean bearing surface at crankshaft end of connecting rodDO NOT use any other type of abrasive clothS Clean crankshaft end of connecting rod by using crocus cloth placed in slotted 38 in(9.5mm) diameter shaft, as shownInsert shaft in drill press and operate press at full speed while keeping connecting rod at 90_ angle to slotted shaftIMPORTANT: Clean connecting rod just enough to clean bearing surfacesDO NOT continue to clean after marks are removed from bearing surfacesS Clean piston pin end of connecting rod, using same method as aboveUse 320 grit carborundum cloth instead of crocus clothS Thoroughly wash connecting rods to remove abrasive gritRecheck bearing surfaces of connecting rodsReplace any connecting rod that cannot be properly polishedLubricate bearing surfaces of connecting rods which will be reused with cycle engine oil to prevent rust