1998 Johnson Evinrude EC 50 thru 70 HP 3-Cylinder Service Manual, Page 156Get this manual
Cleaning
INote Before
inspecting or assembling powerhead, all internal components must be perfectly clean and free of contaminants1Remove any carbon accumulation from exhaust port areas
2Remove any carbon accumulation from cylinder head combustion chambers3If cylinder walls are glazed from extended use, use medium grit cylinder hone to resurface wallsUse slow RPM to achieve strong "crosshatch" pattern for best oil retention and ring sealing
INote To
avoid piston or cylinder block damage, restore the chamfer to all port edges using ball hone or other suitable tool