1997+ Mercury 35/40HP 2 Cylinder Outboards Service Manual PN 90-826148R2, Page 189Get this manual
IMPORTANT: Ports must be deburred after honing CLEANING PISTON RING GROOVES Keystone (tapered) ring grooves
NOTE: The weight of an oversiz piston is approximately the same as standard siz piston; therefore, it is not necessary to re-bore all cylinders in block just because one cylinder requires re-boring5After honing and thoroughly cle aning cylinder bores, apply light oil to cylinder walls to prevent rusting
CAUTION
Care must be taken not to scratch the side surfaces of the ring grooveScratching the side surface of the ring groove will damage the ring groove1Use bristle brush and carbon remover solution to remove carbon from side surfaces2A tool can be made for cle aning the inner diameter of the tapered ring groovesThe tool can be made from broken tapered piston ring with the side taper removed to enable the inside edge of the ring to re ach the inner diameter of the grooveC arefully scrape carbon from inner diameter of ring groovesC are must be taken not to damage the grooves by scratching the side surfaces of the groovesPiston with two half keystone (half tapered) rings