1995 Johnson/Evinrude Outboards 40 thru 55 2-Cylinder Service Manual, Page 154Get this manual
Notellf any cylinder is outside these tolerances, it must be bored oversizeA 0.030 in(0,762 mm) oversize piston is available for this engineTo determine oversize bore add 0.030 in(0,762 mm) to the standard boreRefer to Engine Specifications, Section 1It is permissible to have one or more oversize pistons in an engine []] 9Use micrometer to measure the piston major diameter le in(3,2 mm) above the bottom edge of the piston skirtThe micrometer should be in line with the upper piston ring dowel pin The major diameter should be no smaller than 3.1831 in(80,85 mm) fer standard piston and 3.2131 in(81,61 mm) for an oversize piston1101
10Measure the piston in several more locations le in(3,2 mm) above the bottom edge of the piston skirtNo measurement should be larger than the major diameter and no measurement should be more than 0.004 in(0,10 mm) smaller than the major diameter