Jabiru 3300 - EXCESSIVE VIBRATION; KNOCKING UNDER LOAD

Engine Maintenance Manual
Jabiru Aircraft Pty Ltd
JEM0002-5
Jabiru 2200 & 3300 Aircraft Engines
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ISSUE
1
2
3
4
5
Dated : 2nd June 2015
Issued By: AS
Page: 85 of 103
L:\files\Manuals_For_Products\Engine_Manuals\Engine Maintenance Manual 22 & 33\JEM0002-5.docx
10.13 Excessive Vibration
Possible Cause
Remedy
1)
Propeller out of balance
Balance to propeller manufacturer’s instructions
2)
Propeller tip tracking out of tolerance
Check / adjust tracking
3)
Uneven propeller blade pitch
Check / adjust blade pitch
4)
Spinner out of balance
Check / adjust spinner balance (see Section 0 or
manufacturer’s instructions)
5)
Unsuitable propeller
Replace propeller. Quality 2-bladed fixed pitch wooden types
recommended.
6)
Incorrect Tuning
Check / adjust carburettor
7)
Engine rubbing
Check engine, air ducts, exhaust, oil cooler etc are not
rubbing on cowls, fuselage etc.
10.14 Knocking Under Load
Possible Cause
Remedy
1)
Octane rating too low. Fuel old or stale.
Use fuel with higher octane rating
2)
Spark plug fitted without sealing washer
Ensure one sealing washer on each plug
3)
Heavy carbon deposits
Remove cylinder heads & in combustion chamber
remove deposits. Determine oil consumption.
Notes:
- Running this engine on low octane fuel will cause piston damage and in extreme cases failure
of the top ring gland or holed piston due to detonation.
- Changing the engine tuning to a leaner air fuel mix can cause piston damage.