Ignition System; Spark Plug - Stihl 020 T Service Manual

5.

IGNITION SYSTEM

Warning! Exercise extreme
caution when carrying out
maintenance and repair work on
the ignition system. The high
voltages which occur can cause
serious or even fatal accidents!
The electronic (breakerless)
magneto ignition system basically
consists of an ignition module (1)
and flywheel (2) and is easily
accessible.
STIHL 020 T
5.1

Spark Plug

Troubleshooting on the ignition
system should always begin at the
spark plug.
In the event of starting difficulties,
low engine power, misfiring, etc.,
unscrew the spark plug and check
that it is the approved type. Only the
spark plugs listed in the
specifications may be used. Other
makes of spark plug are unsuitable
because they have longreach
electrodes.
Sooted or carbonized spark
plug:
• Use brass wire brush to clean the
spark plug and then blow it clear
with compressed air.
Note: Never use a steel wire
brush for this job.
Spark plug smeared with oil:
• Wash the insulator nose with a
grease solvent and blow it clear
with compressed air.
Electrode gap:
Electrode gap becomes wider as a
result of normal erosion.
• Check the electrode gap at
regular intervals with a feeler
gauge. It should be 0.5 mm
(0.02").
• Bend the ground electrode as
necessary.
Important: Always fit a new spark
plug if the electrodes are badly
eroded.
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