Engine Maintenance Manual
Jabiru Aircraft
Pty Ltd
JEM0002-5
Jabiru 2200 & 3300 Aircraft Engines
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ISSUE
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Dated : 2nd June 2015
Issued By: AS
Page: 86 of 103
L:\files\Manuals_For_Products\Engine_Manuals\Engine Maintenance Manual 22 & 33\JEM0002-5.docx
10.15 Engine Hard to Start at Low Temperature
– Cold Start Checklist
Possible Cause
Remedy
1) Starter motor condition
Check that the bushes in the starter motor bendix drive housing are in
good condition. Ensure the brushes are not worn out, that the
commutator is clean and all electrical connections are clean. This may
require removing the heat shrink from the soldered connection on the
starter motor and checking for corrosion.
2) Spark plugs
Spark plugs must be within the set life and be gapped correctly. In winter
spark plug gaps can be reduced as low as 0.020” to allow the plugs to fire
more easily
3) High tension leads
High tension leads must be in good condition. Ensure all end terminals
are tight and fitting to the distributor & spark plugs correctly. If necessary
adjust per Section 9.9
. Don’t forget to check the plug where the ignition
coils connect to the distributor cap. Note that running the engine at night
with the cowls removed will make the bright arcs caused by faulty
insulation, bad connections etc much more visible.
4) Distributor assembly
Check that the distributor & rotor are in good condition. Check that there
is no moisture inside the cap and that all the electrical terminals are clean
5) Ignition coil gaps
Check that the coils have been set with the correct air gap from the
flywheel magnets.
6) Air filter
Check that the air filter is clean
7) Fuel filter
Check that the fuel filter is clean
8) Carburettor
Check that the carburettor float level is set correctly and that the
carburettor is clean and in good condition. Ensure there is no debris
blocking jets (including the choke jet) etc
9) Low battery charge
Fit fully charged battery. The life of a Battery varies but is generally less
than 4 years.
10) Operation
Minimise the time spent at low RPM with high-powered devices running.
At low RPM the alternator produce virtually no power
– certainly not
enough to run landing lights, strobe lights and avionics suites. The deficit
between the power draw of these systems and the alternator output must
be drawn from the battery. Excessive operation like this will drain the
battery and significantly reduce the output available for cold starting the
next day
11) Fly regularly
Any vehicle will be harder to start if it goes a long time between outings.
If the aircraft has not been flown for a few weeks then charging the
battery before attempting a start is recommended. Standing also affects
the quality of the fuel in the carburettor and fuel system
– volatile
elements in the fuel can evaporate, making it harder for the carburettor to
atomise it properly
12) Starting method
The recommended procedure is to hold the choke fully ON and the
throttle fully OFF. The Bing carburettor uses an enrichment-type choke
system (as opposed to a butterfly-type choke) which will only work
properly if the throttle is fully closed. When the throttle butterfly is closed
it creates a vacuum which is then used to suck fuel through the choke jet
– if the throttle is not closed there is less vacuum and the choke does not
work as designed. Also note that there is a tendency for the choke to
spring back slightly from the ON position if the knob is released
–
operators are recommended to hold the knob fully ON when starting to
make sure it stays properly on.
13) Idle speed
Ensure that the idle RPM is set correctly. If the idle is too high the throttle
butterfly will be open slightly
– which will prevent the choke from working
properly, as described above. Idle RPM limits are given in the engine
manuals
14) Choke Jet
The choke jet needs to have a bore of about 1.2mm. This gives the
engine more fuel when the choke is applied, making it easier to start.
New engines and aircraft have been set at this size since around
February 2011, however older units will need to be checked and, if
necessary, enlarged. See Figure 48