1995 Johnson/Evinrude Outboards 25, 35 3-Cylinder Service Manual, Page 138Get this manual
6Use telescoping gauge or inside-reading micrometer to inspect each cylinder bore for an out-of-round, oversize, or tapered conditionBe sure the gauge or micrometer is perfectly square in the bore when measuring OJ
7Measure each cylinder in at least two areas as shownEach area should be measured twiceThe difference between the two measurements in each area is the cylinder out-of-round dimension The cylinder must not be out-of-round by more than 0.004 in(0,10 mm)
W 8The dimension difference between the two areas is cylinder taper The cylinder taper must not exceed 0.002 in(0,05 mm)