Testing The Ignition System - Stihl MS 440 Service Manual

: Turn the flywheel until the two
bumps (arrows) are aligned with
the ignition module.
1
: Slide the setting gauge (1)
1111 890 6400 between the arms
of the ignition module and the
raised edge of the flywheel.
– Press the ignition module against
the setting gauge.
: Tighten down the screws of the
ignition module – b 3.5
– Connect the short-circuit wire.
Reassemble all other parts in the
reverse sequence.
46
7.1.3 Testing the ignition
system
Use the ZAT 4 ignition system tester
5910 850 4503 or ZAT 3 ignition
system tester 5910 850 4520 to test
the ignition system.
The ignition test refers only to a
spark test, not to ignition timing!
1 2
Using the ZAT 4 ignition tester
5910 850 4503
– Before starting the test, install a
new spark plug in the cylinder
and tighten it down firmly – b 3.5
: Unplug the boot from the spark
plug and connect it to the input
terminal (1). Push the tester's
output terminal (3) onto the spark
plug.
: Crank the engine quickly with the
rewind starter (min. 1,000 rpm)
and check spark in the tester's
window (2).
Warning!
The engine may start and
accelerate during the test!
If a spark is visible, the ignition
system is in order. If no spark is
visible in the window (2), check the
ignition system with the aid of the
troubleshooting chart – b 7.6.
1
3
Using ZAT 3 ignition tester
5910 850 4520
The ZAT 3 ignition tester
5910 850 4520 must be used to test
the auxiliary spark gap
– Before starting the test, screw a
new spark plug in the cylinder
and tighten it down firmly – b 3.5
: Unplug the boot from the spark
plug in the engine and connect it
to the terminal (2).
: Attach the ground terminal (1) to
the spark plug.
: Use adjusting knob (3) to set the
spark gap to 2 mm (0.79 in).
3
ZAT 3
5910 850 4520
2
MS 440, MS 440 C