1992 Johnson Evinrude "EN" 9.9 thru 30 Service Manual, P/N 508142, Page 187Get this manual
1441 12Use feeler gauge to check groove side clearance on the
lower square ringsInstall each square ring on its pistonWith the ring fully seated in its groove, make several checks around the piston The side clearance must not exceed 0.004 in (0,10 mm)
13Use machinist's straightedge to check clearance on the upper Pressure-BackTM ringsInstall each Pressure-Back ring on its pistonWhen checked with the straightedge, there should be enough ring clearance to allowthe straightedge to touch the piston on both sides of the ring grooveMake several checks around the piston If the straightedge does not touch the piston, remove the ring and clean the ring groove
Assembly Proceed slowlyMake no forced assemblies unless pressing operation is called forAll internal components must be perfectly clean and lightly coated with Johnson or Evinrude Outboard Lubricant