Stihl MS 171 Manual page 41

9. Ignition System
Exercise extreme caution when
troubleshooting and carrying out
maintenance or repair work on the
ignition system. The high voltages
which occur can cause serious or
even fatal accidents.
Troubleshooting on the ignition
system should always begin at the
spark plug, b 4.5
– Remove the fan housing, b 10.1
and b 10.2
1
The electronic (breakerless) ignition
system basically consists of an
ignition module (2) and flywheel (1).
9.1 Ignition Module
1
The ignition module accommodates
all the components required to
control ignition timing. There are
two electrical connections on the
coil body:
40
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– the high voltage output with
ignition lead (1)
– the connector tag (2) for the short
circuit wire
Testing in the workshop is limited to
a spark test.
A new ignition module must be
installed, b 9.1, if no ignition spark
is obtained (after checking that
wiring and stop switch are in good
condition).
Ignition timing is fixed and cannot
be adjusted during repair work.
Since there is no mechanical wear
2
in these systems, ignition timing
cannot get out of adjustment.
9.1.1 Removing and Installing
– Remove the shroud, b 8.4
– Remove the fan housing, b 10.1
and b 10.2
1
2
: Pull off the spark plug boot (1).
: Pull the ignition lead (1) out of the
retainer (arrow).
2
: Pull off the short circuit wire (1).
: Take out the screws (arrows).
: Remove the ground wire (2).
1
: Remove the ignition module (1).
MS 171, MS 181, MS 211
1
1