Ignition Module; Ignition Timing; Removal And Installation - Stihl TS 400 Manual

STIHL TS 400
6.3

Ignition module

All the functional parts for ignition
timing control are combined in the
ignition module. Only two electrical
leads emerge from the coil body:
1. High-voltage output (1)
2. Connector tab (2) for
connecting the stop switch lead
Correct functioning of the ignition
module can only be tested in detail
with the aid of a tester. Repairshop
testing should therefore be limited
solely to spark testing. The complete
ignition module must be replaced if
the ignition spark fails although the
leads and stop switch are intact.
6.3.1

Ignition timing

Ignition in the transistor-controlled
(non-contacting) magneto ignition
is timed at 1.9 mm before UDC at
n = 8000 rpm and cannot be
adjusted.
Taking into account the permissible
variation in electrical control, this
value may vary from 1.6 to 2.2 mm
before UDC at n = 8000 rpm.
These systems are not subject to
mechanical wear. It is therefore
impossible for the ignition timing to
change during operation on account
of wear. Internal defects can,
however, change the switching point
so that spark testing yields a positive
result although the ignition timing is
outside the permissible range and
therefore impairs the machine's
starting and running characteristics.
6.3.2

Removal and installation

• Unscrew the fan cover screws.
- Remove fan cover.
• Disconnect stop switch lead (1)
from the connector tab on the
ignition module.
• Draw the stop switch lead out of
the harness (2).
• Unscrew the ignition module
screws.
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