Supersedes Service Instruction No. 1255 May 13, 2016 MODELS AFFECTED Lycoming engines using thermostatic oil cooler bypass valve TIME OF COMPLIANCE At 100-hour inspection or when high oil temperature is noted REASON FOR REVISION Updated bypass valve replacement part numbers; added respective detailed bypass valve replacement instructions for engines with oil pressure screens and oil filters This...

Supersedes Service Instruction No. 1301A May 13, 2016 MODELS AFFECTED All Lycoming aircraft engines TIME OF COMPLIANCE Any time a fuel line for a fuel injector, primer or fuel manifold are replaced REASON FOR REVISION Update part numbers Fuel lines are to be examined, typically every 100 hours of engine operation or sooner if instructed. If a fuel line is damaged, it is to be replaced with a new...

Supersedes Service Instruction No. 1423 May 13, 2016 MODELS AFFECTED All Lycoming engines using Thermostatic Oil Cooler Bypass Valve Part Number (P/N) 75944 TIME OF COMPLIANCE Before next flight REASON FOR REVISION: Loctite® procedure for crimp nut is no longer valid. New superseding part number for thermostatic oil cooler bypass valve. This revision of the Service Instruction identifies a change...

Supersedes Service Instruction No. 1523F March 16, 2016 MODELS AFFECTED Refer to Table 1 in attached Instruction TIME OF COMPLIANCE As Required for Replacement REASON FOR REVISION Added carburetor part numbers to Table 1 This Service Instruction identifies carburetors from specific manufacturers currently available for Lycoming engine models. Table 1 identifies the carburetor models, Lycoming part...

DATE: March 10, 2016 MODELS AFFECTED All Lycoming engine models. TIME OF COMPLIANCE As required. This Service Instruction contains guidelines for the use of safety cable when installing fasteners or components on Lycoming engine models.

Supersedes Service Instruction No. 1343B March 10, 2016 MODELS AFFECTED The following Wide Cylinder Flange Engines that are equipped with a front crankcase mounted propeller governor: O, IO, LIO, AIO, AEIO-320 Series O, LO, IO, LIO, AIO, AEIO, TO, TIO-360 Series O, IO, AEIO, TIO, LTIO-540 Series IO-580 Series IO-720 TIME OF COMPLIANCE At each installation of propeller governor set screw REASON FOR...

DATE: March 10, 2016 MODELS AFFECTED The following Wide Cylinder Flange Engines that are equipped with a front crankcase mounted propeller governor: O, IO, LIO, AIO, AEIO-320 Series O, LO, IO, LIO, AIO, AEIO, TO, TIO-360 Series O, IO, AEIO, TIO, LTIO-540 Series IO-580 Series IO-720 TIME OF COMPLIANCE At owner’s discretion. This Service Instruction includes inspection instructions for the propeller...

Supersedes Service Instruction No. 1059D January 27, 2016 MODELS AFFECTED All Lycoming opposed series aircraft engines TIME OF COMPLIANCE At engine assembly REASON FOR REVISION Update lubricants This Service Instruction identifies approved factory-tested lubricants for specific engine parts that must be lubricated during engine assembly. Many premature part failures have been caused by incorrect...

Supersedes Service Instruction No. 1458F and Obsoletes Service Instruction Nos. 1106D, 1311A, and 1318 November 10, 2015 MODELS AFFECTED All supported Lycoming reciprocating aircraft engines TIME OF COMPLIANCE Whenever new connecting rods and/or new connecting rod bolts are being installed REASON FOR REVISION Clarified connecting rod bolt selection and installation instructions, added new Figure 1...

Supersedes Service Instruction No. 1526F July 24, 2015 MODELS AFFECTED All Lycoming reciprocating aircraft engines TIME OF COMPLIANCE As required for replacement REASON FOR REVISION Added new piston part number This Service Instruction identifies additional new piston part numbers that superseded existing piston part numbers in the table below. All of the new pistons have been manufactured to be...