1987-1993 Mercury Mariner Outboards 70/75/80/90/100/115HP 3 and 4-cylinder Factory Service Manual, Page 146Get this manual
CYLINDER BORE SIZE Piston Size Standard Diameter .015 Oversize .030 Oversize Cylinder Block Finish Hone 3.375 in(85.725mm) 3.390 in(86.106mm) 3.405 in(86.487mm)
S Measure cylinder bore inside diameter (with an inside micrometer) of each cylinder, as shown belowCheck for tapered, out-of-round ("eggshaped") and oversize bore
S Inspect cylinder bores for scoring (a transfer of aluminum from piston to cylinder wall)Cylinder wall scoring usually can be "cleaned up" by honing or reboring
CAUTION