Ignition System; Ignition Timing - Stihl FS 94 Instruction Manual

6.

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
fatal accidents.
Troubleshooting on the ignition
system should always begin at the
spark plug, b 3.3
– Remove the drive tube, b 9.1
– Remove the fan housing, b 4.1
1
2
The electronic (breakerless) ignition
system basically consists of an
ignition module (1) and flywheel (2).
The ignition module accommodates
all the components required to
control ignition timing. There are
two electrical connections on the
coil body:
1. High voltage output with
fixed ignition lead.
2. Fixed wire with
cable lug for the
short circuit wire.
36
Testing in the workshop is limited to
a spark test. A new ignition module
must be installed if no ignition spark
is obtained (after checking that
wiring and stop switch are in good
condition).
6.1

Ignition Timing

Ignition timing is fixed and cannot
be adjusted during repair work.
Since there is no mechanical wear
in these systems, ignition timing
cannot get out of adjustment during
operation.
6.2 Install new ignition
module
– Troubleshooting, b 3.3
– Remove the shroud, b 5.4
– Remove the fan housing, b 4.1
– Pull boot off the spark plug.
– Remove the drive tube, b 9.1
1
2
: Disconnect the flag terminal (1)
and pull the short circuit wire (2)
out of the guide (arrow).
1
2
: Take out the screws (1) with
washers and remove the ignition
module (2).
– Check ignition module and lead,
replace ignition module if
necessary
Installing
2
1
: Fit the ignition module (1) and
insert the screws (2) with
washers – do not tighten down
yet.
Series 4149 Powerhead
1
2