INSTRUCTION AND MAINTENANCE MANUAL FOR JABIRU 2200 ...

Jabiru Aircraft Pty LtdInstruction & Maintenance ManualJabiru 2200 Aircraft EngineHydraulic Valve Lifter ModelsThe carburetor automatically adjusts the mixture to account for altitude.IMPORTANT Check carburetor joints for degradation. Check carburetor linkage for full & free movement, correct positioning of stops andsecurity.6.4 Compression Check6.4.1 Compression Gauge:Measure compression using a compression tracer. Readings are taken with fully openthrottle valve at engine oil temperature between 30° & 70°C (90° to 160°F).If readings are below 6 bar (90 psi) a check of the pistons, cylinders, valves & cylinderheads must be undertaken.6.4.2 Pressure Differential Test: Check using a pressure loss or leakage tester eg SUN or BOSCH tester; max.allowable pressure loss is 25%.As an alternative to a compression test, a pressure differential test (Leak down) can becarried out. This is a much better test of the condition of rings, bore, head sealing andvalve. This is the normal test used in aviation and requires specific equipment.The test is carried out with the engine in warm to hot condition. Input pressure is bestset at 80 PSI; a second gauge reads the differential. This is done with piston on TDCon the firing stroke. Note that the propeller needs to be restrained. A differential oflower than 80/60 (or generally, a 25% loss) indicates a problem.Problems can be better identified using the leak down:i) Blow by through the crankcase vent indicates worn rings or boreii) Leaking from carby indicates a poor intake valve sealiii) Leaking from exhaust indicates a poor exhaust valve sealiv) Head leak indicates poor head to cylinder sealWith the problem narrowed down, correction work can more easily be carried out.A Pressure Differential Tester can be made by placing an orifice of 1 mm ID and 3mmlength between two pressure gauges. This will give the same result as with the aboveinstrument. Max. pressure drop is 25%.CAUTION: Poor compression can be an indication of a serious problem. Forexample, continued operation with poor compression due to a poorly-sealing valve canlead to eventual valve failure and heavy damage to the piston, con-rod, barrel andhead. If low compression is found which cannot be solved by reference to theTroubleshooting section below, please contact Jabiru Aircraft or our localauthorized representative.This document is controlled while it remains on the Jabiru server. Once this no longer applies the document becomes uncontrolled.REVISION 0 1 2 3 4 5 6 7 8 9 Dated : June 2010 Issued By: DPS Page: 29 of 116L:\files\Manuals_For_Products\Engine_Manuals\Transition\JEM2204-9_I&M_unsigned.docx