Yamaha F8F Owner's Manual

Also see for F6D: Ower's manual

Maintenance69EMU44493Cleaning and adjusting spark plugThe spark plug is an important engine com-ponent and is easy to inspect. The conditionof the spark plug can indicate somethingabout the condition of the engine. For exam-ple, if the center electrode porcelain is verywhite, this could indicate an intake air leak orcarburetion problem in that cylinder. Do notattempt to diagnose any problems yourself.Instead, take the outboard motor to aYamaha dealer. You should periodically re-move and inspect the spark plug becauseheat and deposits will cause the spark plug toslowly break down and erode.(1) Remove the spark plug caps from thespark plugs.(2) Remove the spark plug. If electrode ero-sion becomes excessive, or if carbonand other deposits are excessive, youshould replace the spark plug with an-other of the correct type. WARNING!When removing or installing a sparkplug, be careful not to damage the in-sulator. A damaged insulator could al-low external sparks, which could leadto explosion or fire. [EWM00562](3) Be sure to use the specified spark plug,otherwise the engine may not operateproperly. Before fitting the spark plug,measure the electrode gap with a wirethickness gauge; replace it if out of spec-ification.(4) When fitting the plug, wipe off any dirtfrom the threads, and then screw it in tothe correct torque.TIP:If a torque-wrench is not available when youare reinstalling a spark plug, a good estimateof the correct torque is 1/12 turn past finger-tight. When you are installing a new sparkplug, a good estimate of the correct torque is1/2 to 2/3 turn past finger-tight.1. Spark plug capStandard spark plug:BR6HS-1011. Spark plug gap2. Spark plug part number3. Spark plug I.D. mark (NGK)Spark plug gap:0.9–1.0 mm (0.035–0.039 in)Spark plug torque:24 N·m (2.4 kgf·m, 18 lb·ft)112233