1992 Johnson Evinrude "EN" 90 deg. Cross V Service Manual, P/N 508145, Page 176Get this manual
1721 10Use micrometer to check piston conditionMake at least two measurements, 90 from each otherMeasure the piston diameter 114 in(6,4 mm) above the bottom edgeRefer to Engine
Specif icat ions, Section 1, for piston dimensions The difference between the two piston measurements must not exceed 0.004 in(0,10 mm)
1731 11For 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 gap 85 thru 155 Commmodelsthe ring end gap must be within 0.019-0.031 in(0,48-0,79 mm)
1741 12Use feeler gauge to check groove side clearance on the
lower, square ringsInstall each square ring on its piston With the ring seated in its groove, make several checks around the piston The side clearance must not exceed 0.004 in(0,10 mm)