Service Instruction No. 1485 B

Exhaust Valve and Guide Identification Procedure

Publications
DATE:

July 30, 2026

SUBJECT:

Exhaust Valve and Guide Identification Procedure

MODELS AFFECTED:

All Lycoming reciprocating aircraft engines unless installed in a rotary-wing aircraft.

TIME OF COMPLIANCE:

Every 1000 hours of operation or earlier at owner’s discretion or anytime valve
sticking is suspected.

REASON FOR REVISION:

Revised paragraph and updated inspection time interval to align with extended TBO’s. Added ICA statement. Added NOTICE. Changed NOTE to NOTICE.

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