SWM SM 500 R E4 2018, Manual

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0,7 ÷ 0,8 mm
1
3
2
4
5
EN
EN - 33
SPARK PLUG CHECK
Spark plug (2) gap shall be 0.028 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.
To remove the spark plug, do the following:
- Unscrew the screws (1).
- Lift the coil (2) complete with clamp (3) and
disconnect the connector (4).
- Clean the base of the spark plug (5) and then
remove it.
It is very useful to examine the state of the spark
plug just after it has been removed from the engine
since the scale deposits on the plug and the colour
of the insulator provide useful indications.
Correct heat rating:
The tip of the insulator should be dry and the colour
should be 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 in-
sulator tip is vitrified (glazed), white or grey in col-
our.
WARNING*: If the spark plug is replaced, use
one with the same rating.
CAUTION*: A spark plug with too hot a heat
range may lead to preignition and possible
engine damage. A spark plug with too cold a
heat range may foul as the result of too much
carbon buildup.
Before refitting the plug, thoroughly clean the
electrodes and the insulator using a metal
brush. Smear some graphite grease on spark
plug thread, do it fully home finger tight then
tighten it to 7.37÷8.85 ft-lb. torque. Loosen the
spark plug then tighten it again to 7.37÷8.85
ft-lb.
Spark plugs which have cracked insulators or
corroded electrodes should be replaced.