Yamaha F40H Owner's Manual

Also see for F40G: Owner's manual

Maintenance77(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 turn past finger-tight.EMU29045Inspecting idle speedEWM00452 Do not touch or remove electrical partswhen starting or during operation. Keep hands, hair, and clothes awayfrom the flywheel and other rotatingparts while the engine is running.ECM00491This procedure must be performed whilethe outboard motor is in the water. Aflushing attachment or test tank can beused.If the boat is not equipped with a tachometerfor the outboard motor, use a diagnostic ta-chometer for this procedure. Results mayvary depending on whether testing is con-ducted with the flushing attachment, in a testtank, or with the outboard motor in the water.(1) Start the engine and allow it to warm upfully in neutral until it is running smooth-ly.(2) Once the engine has warmed up, verifywhether the idle speed is set to specifi-cation. For idle speed specifications, seepage 12. If you have difficulty verifyingthe idle speed, or the idle speed requiresadjustment, consult a Yamaha dealer orother qualified mechanic.EMU38808Changing engine oilEWM00761 Avoid draining the engine oil immedi-ately after stopping the engine. The oilis hot and should be handled with careto avoid burns. Be sure the outboard motor is securelyStandard spark plug:DPR6EB-9 (F40HET, F50HED,F50HET, F60FET, FT50JET,FT60GET)LKR7E (F40GET, F70AET)1. Spark plug gap2. Spark plug part number3. Spark plug I.D. mark (NGK)Spark plug gap:0.8–0.9 mm (0.031–0.035 in)Spark plug torque:17 N·m (1.7 kgf·m, 13 lb·ft)123