Husqvarna K 960 Workshop Manual page 13

6
C B
2
3
0.5 mm
.02 in.
12
IGNITION SYSTEM
2
+
Volts
Ignition
point
0
3
-
1
Electronic
circuit
A D breaker
STOP
1
control
Ignition module
Individual components can not
be replaced.
unit to the spark plug and seals
on the ignition module can be
replaced.
(arrow) is connected to the stop
switch.
Spark plug
The spark plug's electrode gap
should be .02 in./0.5 mm.
Function
The ignition system is fully enclosed and has no moving
parts. It is insensitive to moisture and dirt. The design is
such that the ignition point does not need to readjustment.
Husqvarna K960 has integrated overspeed protection in the
electronic unit that limits the engine's speed to 9,300 rpm.
The ignition system consists of the primary coil (A) and
secondary coil (B) which are both surround ed by the iron
core (C). An electronic digital unit (D) manages the switch
function.
Current is generated in the primary coil when the fly -
wheel's permanent magnet passes the coil and has the voltage
sequence illustrated in the diagram. (The dashed line indi -
cates the voltage that should be generated if the current is
not broken.)
The ignition point is determined by the electronic unit,
which sense the voltage variation in the primary coil and
breaks the current at the right level, at the same time the
engine piston is just below the upper turning point. At the
breaking instant the voltage in the primary coil rises from
5 V (volt) to approximately 200 V through induction. At the
same time a high voltage, approximately 20,000 volt, is
transformed in the secondary coil to the spark plug.
The ignition lead, contact
The short-circuit contact
Ignition module
The ignition module's components are
fully enclosed to withstand external
manipulation. Individual components
can not be replaced.
The ignition lead, contact unit to the
spark plug and seals on the ignition
module can be replaced.
The ignition module requires no perio-
dic servicing. (Nevertheless, the distance
to the flywheel's magnet may need
adjusting.)
The ignition module has two connec-
tions. One to the spark plug and the
other is the short-circuit contact (arrow)
to the stop switch.
Spark plug
The spark plug's electrode gap should be
.02 in./0.5 mm.
The electrodes should be free of soot
deposits and oil. Brush clean with a wire
brush.
A convex centre electrode and a worn
side electrode impair the ignition charac-
teristics. Replace the spark plug.