Yamaha Marine Outboards F4A/F4 Factory Service Manual, Page 294Get this manual
ELEC IGNITION SYSTEM
SPARK PLUG CAP (STANDARD)
2 1Inspect: 9Spark plug cap Cracksdamage Replace9Plug cap spring DeformityDamage Replace
Replacement steps: (standard type) Remove the high-tension cord from the spark plug cap by pulling it8 Remove the plug cap spring and lift up from the high-tension cord 28 Cut off the end of the high-tension cord about length aLength a: mm (0.2 in) Strip off cord end about and fit the plug cap spring 38 To fit the high-tension cord to the spark plug cap push into the plug cap8 Bind the plug cap bottom tightly with the clamp clip and fasten it