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Jabiru Aircraft
Pty Ltd
Installation Manual
Jabiru 3300 Aircraft Engine
REVISION
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Dated : 1
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Dec 2016
Page: 18 of 56
4.8
Instruments
4.8.1
Electronic Tachometer
General wiring information for the Tachometer is given in the Wiring Diagram, Figure 26. Detailed
instructions on it’s installation are supplied by the instrument manufacturer.
The tachometer picks up on 2 metal tabs attached to the inside of the flywheel.
The Pickup used is a Magnetic Induction sender type. It is a passive device requiring no external power.
They Pickup outputs a voltage in response to variations in their self-induced magnetic field caused by
proximity to moving ferrous metal parts (such as the tags fitted to the rear of the flywheel).
The Tachometer sender must be adjusted to have approximately a 0.4mm gap between the tip of the sender
and the tag. Note that due to normal bearing clearances the crankshaft moves slightly when the engine is
running, so if this gap is set too small the sender will hit the tag. The sender is fragile and most times
damage like this means that the sender must be replaced. If the gap is different for each of the two tags
then one tag can be carefully bent to be the same as the other.
Ensure gauge is reading correctly. While large errors will be obvious, smaller errors are harder to pick and it
is recommended to check the gauge reading with another instrument (such as a hand-held optical prop-
tach).
Figure 15. Tachometer Sender Installation
Figure 16. Tachometer Connections
Tachometer Sender
8 7 6 5
4 3 2 1
Connect to Earth Bus
Connect to positive, such as
the Instrument Wiring Bus
Connect to Black wire of
tachometer pick-up
Connect to Red Wire of
tachometer pick-up