Compression Check For Fault-Tracing - Rotax 912 i Series Maintenance Manual

COMPRESSION CHECK FOR FAULT-TRACING

General note Official and accepted measurement method is the differential pressure check, it is possible
to check the engine with a compression check method when differential pressure check
reading is unclear. Mainly - always perform the differential pressure check. In the course
of fault-tracing a compression check can also be performed.
A compression tester is required to check compression. The compression should be be-
tween 9 and 12 bar (130 psi and 174 psi).
Instruction Compression check for fault-tracing.
Step
Measurement Individual readings for the cylinder must not differ by more than 2 bar (29 psi).
If the value is below 6 bar (87 psi), inspection, repair or overhaul must be carried out in ac-
cordance with the BRP-Rotax instructions for continued airworthiness
• Detailed inspection of affected engine components.
Effectivity: 912 i Series
Edition 2/Rev. 0
BRP-Rotax
MAINTENANCE MANUAL LINE
All LANE select switches must be "OFF".
Procedure
1
Operate the engine until the temperatures have stabilized for a period of 5
min (engine oil temperature between 50 to 70 °C (122 - 160 °F).
2 Unscrew and remove top spark plugs.
3 Press compression tester (1) over the spark plug hole and use the starter to
turn the engine over with open throttle until maximum pressure is reached.
4 Successively take readings on all four cylinders and compare results.
m WARNING
Keep the propeller area clear!
12–20–00
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September 01/2018