January 23, 2014 To all owners and operators of Lycoming engine model O-360-A4M installed in Piper Archer III with AVStar carburetor model AV10-6102. This Service Letter is notification of the following two product improvements by AVStar to carburetor model AV10-6102 (Lycoming P/N 61C26051). These product improvements have been incorporated into new O-360-A4M engines with Serial Numbers L-42322...

August 27, 2013 To all Lycoming Engine Owners, Operators, and Authorized Lycoming Distributors This Service Letter is to advise customers, operators and authorized Lycoming distributors that External Retaining Ring P/N MS16624­37 is superseded by P/N MS16624­2037 External Retaining Ring (zinc coated).

April 15, 2013 To all Owners and Operators of Lycoming Piston Aircraft Engines Lycoming Engines’ naming convention for carburetor model designations is identified in the following table. The naming convention is intended to prescribe the general feature set specification of the carburetor and does not constitute the complete specification of the product.

DATE: November 16, 2007 SUBJECT Clearance Between Oil Sump Assembly and Oil Sump Baffle. MODELS AFFECTED New, rebuilt, overhauled, or repaired Lycoming IO­540­L1C5; TIO­540­ S1AD; IO­580­B1A series engines. TIME OF COMPLIANCE Whenever rivets or screws are found in the oil suction screen. Lycoming has determined that on the above affected engines there may not be enough clearance between the oil...

Supersedes Service Letter No. L220B To All Lycoming Engine Owners, Operators, and Authorized Lycoming Distributors MODELS AFFECTED All Lycoming engines made since July 1, 1987 except O-235 engines This Service Letter is an informational document about wide deck cylinders on Lycoming aircraft engines. Except for O-235 series engines, Lycoming Engines has made all new engines with a “wide deck...

Supersedes Service Letter No. L250 To all Lycoming Engine Owners, Operators, and Authorized Lycoming Distributors This Service Letter communicates to Lycoming engine owners and operators Lycoming Engines’ exchange engine core policy.

January 14, 2011 To all Owners and Operators of Lycoming O-235 Aircraft Engines This Service Letter introduces the new upgraded O-235 crankcase and associated replacement part numbers available as an option to replace the existing O-235 crankcases.

November 23, 2010 To all Lycoming Engine Owners, Operators, and Authorized Lycoming Distributors This Service Letter is a notice that recent lots of connecting rod bolts P/N 75060 have a variant marking of the part number on the bolt head as shown in Figure 1. Figure 2 shows the typical marking. The bolt with the variant marking (in Figure 1) can still be used. It will not change measurements for...