1990 Johnson Evinrude "ES" 60 thru 70 Service Manual, P/N 507873, Page 143Get this manual
1411 9Use micrometer to check piston condition Make at least two measurements, 90 from each otherMeasure the piston diameter 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)
1421 10For new or used ring sets, make the following inspec-
tionsPlace each ring, separately, in its respective boreUse piston to square the ring in the cylinderUse feeler gauge to measure the ring end gap The ring end gap must be within 0.007-0.017 in(0,13-0,46 mm)
1431 11 Use feeler gauge to check groove side clearance on the