Stihl FC 90 - Page 54

53Series 4180 Powerhead
: Take the screw (1) out of the fan
housing and remove the engine.
Support the engine so that it
does not drop when the screw is
removed.
VA
249RA060
1
: Release and remove screw (1)
with connector tag.
: Take out the screw (2) with
washer.
: Remove the ignition module.
VA
249RA098
1
2
Depending on the type of cylinder,
the ignition module is mounted to
the cylinder with or without washers.
The height of the cylinder bosses for
mounting the ignition module are
different:
: a = 6.7 mm: Mount ignition
module without washers
: a = 4.7 mm: Mount ignition
module with washers
249RA194 BL
a
: In this case, fit the washers (1)
between the cylinder and ignition
module.
249RA195 BL
1
1
Both models
: Slide the setting gauge
4118 890 6401 (2) between the
arms of the ignition module (1)
and the flywheel (3).
– Press the ignition module against
VA
249RA099
1
2
3
the setting gauge.
– Tighten down the screws, b
3.4
Reassemble all other parts in the
reverse sequence.
To test the ignition module, use
either the ZAT 4 ignition system
tester 5910 850 4503 or the ZAT 3
ignition system tester
5910 850 4520.
The ignition test refers only to a
spark test, not to ignition timing.