1996 Johnson/Evinrude Outboards 50 thru 70 3-Cylinder Service Manual, Page 159Get this manual
[] 9Use micrometer to check piston conditionMake at least two measurements, 90 from each otherMeasure the piston diameter V4 in(6,4 mm) above the bottom edgeRefer to Engine Specifications, Section 1, for piston dimensions The difference between the two piston measurements must not exceed 0.003 in(0,08 mm)I]]
10For new or used ring sets, make the following inspectionsPlace each ring, separately, in its respective boreUse piston to square the ring in the cylinderUse feeler gauge to measure the ring end gapThe ring end gap must be within: Recreational Models0.019-0.031 in(0,48-0,79 mm) Commercial Models0.010-0.022 in(0,25-0,56 mm)