1988 Johnson Evinrude "CC" 9.9 thru 30 Service Manual, P/N 507660, Page 195Get this manual
Cleaning
INote Before inspecting or assembling powerhead, all
internal components must be perfectly clean and free of contaminants 1Remove any carbon accumulation from exhaust port areas
2Remove any carbon accumulation from cylinder head combustion chambers 3If cylinder walls are glazed from extended use, use medium grit hone to resurface walls Use slow RPM to achieve strong "crosshatch" pattern for best oil retention and ring sealingTo avoid piston or cylinder block damage, restore the chamfer to all port edges using ball hone or other suitable tool
i gloves when using OMC Gel Seal and Gasket Remover
'" To avoid personal injury, wear eye protection and rubber
Use OMC Gel Seal and Gasket Remover to remove all traces of gaskets, adhesives, and Gel-Seal II from the cylinder block and crankcase