Service Instruction No. 1539

Fuel Manifold Spring Change

  • Publications

DATE: February 4, 2011


AEIO-540-D4B5 Model Engine Installed in H.A.L. HPT-32 Aircraft.


At owner’s discretion.

This Service Instruction identifies a new 4 psi flow divider spring Precision P/N 2577011 that is available as a replacement for the 2 psi flow divider spring for improved idle characteristics, especially in hot weather, for Lycoming engine model AEIO-540-D4B5. This Service Instruction is NOT a substitute to adjusting the fuel system and idle RPM. A check of the fuel adjustment must be done after the spring is installed.

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