1998 Johnson Evinrude "EC" 9.9 thru 30 HP 2-Cylinder Outboards Service Manual, Page 174Get this manual
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 allow the 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 grooveAssembly
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
1lightly lubricate the three water deflectors with STP Oil TreatmentInstall the two long and one short water deflectors until they are flush, or nearly flush, with the gasket surface