Service Instruction No. 1424 A

Installation Procedure for P/N 15B26066 Hydraulic Tappet/Plunger Assemblies

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Supersedes Service Instruction No. 1424

December 15, 2009


All Lycoming reciprocating engines using P/N 15B26066 except: O-235 series; O-320-H series; O, LO, TO, LTO-360-E series; and TIO, TIGO-541 series.


Any time new P/N 15B26066, hydraulic tappet plunger assemblies, are installed.

Whenever a new plunger assembly is installed, perform the following steps to ensure that the plunger does not stick in the collapsed position.

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