Jabiru Aircraft
Pty Ltd
Installation Manual
Jabiru 3300 Aircraft Engine
REVISION
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Dated : 1
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Dec 2016
Page: 16 of 56
4.3
Ignition
The ignition unit is a dual breakerless transistorised ignition with the magnets mounted on the flywheel and
the coils mounted on the alternator mount plate. Figure 9 shows the coils of a Jabiru 6-cylinder engine.
The current from the coils flows to the distributor from where it is distributed to the spark plugs.
The ignition is turned OFF by grounding the coils via the ignition switches. This is the reverse of most
electrical systems: when the ignition switch is in the open (not connected) position the coil is LIVE and will
fire. Wiring details are shown in Figure 26.
The ignition is timed to 25° BTDC. Ignition timing is fixed
– it is set by the position of the flywheel magnets
relative to the crankshaft.
The temperature limit for the ignition coils is approximately 70°C. This should be checked by the installer. It
is recommended that pipes of 12mm dia be fitted to the top rear of each air duct directing air onto the coils
for cooling purposes.
Coil gaps are set at 0.25mm to 0.30mm
(0.010” to 0.012”).
When installing new ignition coils the output leads go in the directon of prop rotation. RHS coil output lead
is up LHS coil output lead goes down
– See Figure 9.
Figure 13. Ignition Coil Cooling Tube
4.4
Starter Motor
The starter is mounted on the top of the engine and drives the ring gear on the flywheel.
The motor is activated by engaging the starter button (the master switch has to be ON) which trips the
solenoid, hence current flows from the battery to the motor.
The cable from Battery to starter should be minimum 16mm
2
copper.
Wiring details are shown in Figure 26.
4.5
Starter Solenoid
The starter Solenoid is mounted on the firewall as shown in Figure 11.
The Solenoid body forms a part of the electrical circuit and MUST be earthed to function correctly.
Ram air cooling duct
Coil cooling tube
Ignition coil