SPARK PLUG CHECK
Spark plug gap (2) must be 0.7- 0.8 mm (0.28- 0.31 in.).
A wider gap may cause difficulties in starting the
engine and overload the coil.
A gap that is too narrow may cause difficulties when
accelerating, when idling or poor performance at low
speed.
Disconnect the connector (1).
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Loosen the two screws (2), remove the locking plate
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(3), then remove the cap (4) complete with coil from
the spark plug.
Clean the base around the spark plug before
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removing it.
30
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IT is very useful to examine the status of the spark
plug just after it has been removed from its seat, since
the deposits and the colour of the insulator provide
useful information.
Correct heat rating:
The tip of the insulator is dry and the colour is light
brown or grey.
High heat rating:
In this case, the insulator tip is dry and covered with
dark deposits.
Low heat rating:
In this case, the spark plug has overheated and
insulator tip is vitrified (glazed), white or grey in colour.
WARNING
Change the spark plug, if necessary, using
one having the same rating.
WARNING
A spark plug with heat rating too high can
cause pre-ignition and possible engine
damage. A spark plug with heat rating
too low can cause a significant increase in
carbon deposits.
CAUTION
Before refitting the plug, thoroughly clean
the electrodes and the insulator using a
metal brush. Smear graphite grease on
spark plug thread, manually screw it fully
home, then tighten it to a torque of 10÷12
Nm (7.37÷8.85 ft/lb). Loosen the spark
plug then tighten it again to 10÷12 Nm
(7.37÷8.85 ft/lb).
Spark plugs with cracked insulators or
corroded electrodes should be replaced.
Refit the cap with coil (4) on the spark plug.
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Refit the locking plate (3) and tighten the two screws
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(2) to 7 Nm (0.7 Kgm - 5.1 ft/lb).
Reconnect the connector (1).
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