Spark Plug - Yamaha 25J Manuel D'entretien

INSP
ADJ
PERIODIC SERVICE
D35000-0*

SPARK PLUG

1. Check the electrode 1 condition and
state of wear, note the insulator 2 color
and the electrode gap.
Normal condition is a medium to light
tan color.
Distinctly different color → Check the
engine condition.
Whitish color : Lean fuel mixture
Blackish color : Electrical malfunction
2. Clean the spark plug with spark-plug
cleaner or wire brush. Use a wire gauge
to adjust the plug gap a to specifica-
tion.
Spark plug gap:
0.9 ~ 1.0 mm (0.035 ~ 0.039 in)
3. If the electrode becomes too worn,
replace the spark plug.
Standard spark plug:
NGK B7HS-10
NGK BR7HS-10
(Noise suppressor type)
4. When installing the spark plug, clean
the gasket surface, wipe off any grime
there may be on the surface of the spark
plug, and screw in the spark plug to the
correct torque.
Tightening torque:
20 Nm (2.0 m • kgf, 14 ft • lb)
NOTE:
Screw spark plug in finger-tight a, then
torque spark plug to specification b.
3-18
Plugged filter, jet
Air leak
Wrong settings
Defective spark plug
Defective ignition system
Rich mixture
Excessive idling
E