Mercury 35/40HP 2 Cylinder Outboards Service Manual PN 90-42794--1, Page 81Get this manual
Cleaning Piston Ring Grooves A broken rectangular piston ring can be used as tool for scraping carbon from ring groovesCarefully scrape carbon from ring grooves without scratching the side surfaces of grooves
Connecting Rods
If necessary, clean connecting rod bearing surfaces, as follows: aBe sure that "etched" marks on knob side of connecting rod (crankshaft end) are perfectly aligned with "etched" marks on connecting rod capTighten connecting rod cap attaching bolts securely
ACAUTION
Crocus cloth MUST BE USED to clean bearing surface at crankshaft end of connecting rodDO NOT use any other type of abrasive clothbClean CRANKSHAFT END of connecting rod by using CROCUS CLOTH placed in slotted 38 in (9.Smm) diameter shaft, as shownCheck shaft in drill press and operation press at high speed while keeping connecting rod at 90 angle to slotted shaftIMPORTANT: Clean connecting rod just enough to clean up bearing surfacesDO NOT continue to clean after marks are removed from bearing surfacescClean PISTON PIN END of connecting rod, using same method as in Step "b," preceding, but using 320 grit carborundum cloth instead of crocus cloth