2006 Johnson SD 30 HP 4 Stroke Outboards Service Manual, PN 5006592, Page 166Get this manual
POWERHEAD PISTON, CYLINDER, AND CRANKSHAFT IMPORTANT: The top compression ring differs from the second compression ring in shape and color of the surface contacting the cylinder wallshownFailure to stagger the piston ring gaps may result in crankcase oil dilution 3,4
2-1234Top compression ring Oil ring lower side rail 2nd compression ring Oil ring upper side rail
1Top compression ring 22nd compression ring 3Oil ring
IMPORTANT: The top compression ring and the
second compression ring are marked "RN" or "R"When installing these piston rings, the marked side must face toward the top of the piston