Mercury Mariner 4, 5 102CC Sail 1990 Outboard Service Shop Manual, Page 64Get this manual
MEASURING CYLINDER BORE , Measuring cyl inder ore al th ree depths by positioning measu ring in strument in-line with and at right angles (90 degrees) to piston pin ce nte li ne (six places) 2If the cyl inder bore is excessive ly scored, is tapered out-at- round more an 0.003 in(O.OSmm), if the piston clearance is more than 0.0024 (O.6mm)it will be necessary to rebare the cylinder to accept the next ove rsize piston
FOLLOWING HONING
1Thorough ly clean cylinder bore with hot water and dete rgentScru well with st iff bristle brush and rinse thoroughly with hot water2C lean remainder of cylinder block to re move excess materia spread during honi ng operation
3Apply light il to cyl inder wall to prevent rusting
Pistons
1Clea carbon deposits from top pi sto with soft wi re bru sh carbon remo val solution or bead blasting When wire brushing top of piston do not burr or round mac hined edgesClean (polish) piston skirt with roc us cloth