1988 Johnson/Evinrude "CC" 40 thru 55 Models Service Manual, Page 126Get this manual
Spark Plug Information The spark plugs should be removed and examinedThe spark plugs should be replaced if the electrodes are badly worn, have cracked insulator, or are badly fouledBefore installing the high tension lead cover on the spark plug, apply light coating of OMC TripeGuard grease to the ribbed portion of the spark plug ceramic and to the opening of the spark plug coverThis will help prevent corrosion of the spring terminal on the spark plug which can cause high tension arcing