Stihl MS 390 User Manual

40 MS 290, MS 310, MS 390
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
Using the ZAT 3 ignition tester
5910 850 4520
– Before starting the test, install a
new spark plug in the cylinder
and tighten it down firmly, b 3.5
: Remove spark plug boot and
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2
ZAT 3
5910 850 4520
3 4
1
connect it to terminal (2).
: Attach ground terminal (1) to the
spark plug.
: Use adjusting knob (4) to set
spark gap to about 2 mm.
: If a spark is visible in window (3),
the ignition system is in order.
While using the ZAT 3, hold it only
by the handle (4) or position it in a
safe place. Keep fingers or other
parts of your body at least 1 cm
away from the spark window (3),
high voltage connection (2), ground
connection (5) and the ground
terminal (1).
Warning!
High voltage – risk of electrocution.
– Crank the engine quickly with the
rewind starter (min. 1,000 rpm)
and check sparkover in the
tester’s window (3).
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 (3), check the ignition
system with the aid of the
troubleshooting chart, b 7.6
– Troubleshooting – b 4.4
– Remove the handle housing, b
9.2
– Pull the boot off the spark plug.
: Use suitable pliers to pull the leg
VA
212RA236
spring out of the spark plug boot.
– Unhook the leg spring from the
ignition lead.
– Pull the boot off the ignition lead.
– Cut new ignition lead to a length
of 175 mm.
– Coat end of ignition lead (about
20 mm) with oil.
– Fit the spark plug boot over the
ignition lead.
Install in the reverse sequence.
7.2 Spark Plug Boot

Stihl MS 390 Specifications

General

Brand	Stihl
Model	MS 390
Category	Chainsaw
Language	English