Yamaha WaveRunner FX140 Service Manual page 69

INSP
ADJ
POWER UNIT
3. Inspect:
• Electrodes 1
Damage/wear → Replace.
• Insulator color 2
Distinctly different color → Check the
engine condition.
Color guide:
Medium to light tan color:
Normal
Whitish color:
Lean fuel mixture
Air leak
Incorrect settings
Blackish color:
Overly rich mixture
Electrical malfunction
Defective spark plug
4. Clean:
• Spark plug
(with a spark plug cleaner or wire brush)
5. Measure:
• Spark plug gap a
Out of specification → Regap.
Spark plug gap:
0.7–0.8 mm (0.028–0.031 in)
6. Tighten:
• Spark plug
Spark plug:
13 N • m (1.3 kgf • m, 9.4 ft • lb)
NOTE:
• Before installing the spark plug, clean the
gasket surface and spark plug surface. Also,
it is suggested to apply a thin film of anti-
seize compound to the spark plug threads to
prevent thread seizure.
• If a torque wrench is not available, a good
estimate of the correct tightening torque for a
new spark plug is to finger tighten a the
spark plug and then tighten it another 1/4 to
1/2 of a turn b.
3-22
E