2002/2003 Johnson SN/ST 2 Stroke 3.5, 6 8 HP Outboards Service Manual, PN 5005466, Page 148Get this manual
POWERHEAD CLEANINGALL MODELS
CLEANINGAll Models
IMPORTANT: Before inspecting or assembling
powerhead, all internal components must be perfectly clean and free of contaminantsRemove any carbon accumulation from exhaust port areasRemove any carbon accumulation from cylinder head combustion chambersIf cylinder walls are glazed from extended use, use medium grit hone to resurface wallsUse slow RPM to achieve strong "crosshatch" pattern for best oil retention and ring sealing
Carefully remove any carbon accumulation from the tops and ring grooves of the pistonsA ring groove cleaning tool can be made by breaking an old ring and grinding an angle on its endDO NOT damage ring grooves while cleaning
IMPORTANT: To avoid piston or cylinder block damage, restore the chamfer to all port edges using ball hone or other suitable tool