Yamaha 25D Owner's Manual

Also see for 25D: Owner's manual

Contents

Maintenance40ple, 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 plugto slowly break down and erode. If electrodeerosion becomes excessive, or if carbon andother deposits are excessive, you should re-place the spark plug with another of the cor-rect type.Before fitting the spark plug, measure theelectrode gap with a wire thickness gauge;adjust the gap to specification if necessary.When fitting the plug, always clean the gas-ket surface and use a new gasket. Wipe offany dirt from the threads and screw in thespark plug to the correct torque.NOTE:If a torque-wrench is not available when youare fitting a spark plug, a good estimate ofthe correct torque is 1/4 to 1/2 a turn past fin-ger-tight. Have the spark plug adjusted to thecorrect torque as soon as possible with atorque-wrench.EMU28962Checking fuel systemWARNINGEWM00060Gasoline and its vapors are highly flam-mable and explosive. Keep away fromsparks, cigarettes, flames, or othersources of ignition.WARNINGEWM00910Leaking fuel can result in fire or explo-sion. Check for fuel leakage regularly. If any fuel leakage is found, the fuelsystem must be repaired by a qualifiedmechanic. Improper repairs can makethe outboard unsafe to operate.Check the fuel lines for leaks, crack, or mal-function. If a problem is found, your Yamahadealer or other qualified mechanic should re-pair it immediately.Standard spark plug:B7HS-10BR7HS-101. Spark plug gap2. Spark plug I.D. mark (NGK)Spark plug gap:0.9–1.0 mm (0.035–0.039 in)Spark plug torque:25.0 Nm (18.4 ft-lb) (2.55 kgf-m)