Supersedes Service Letter No. L173B March 10, 2006 Models Affected To Owners and Operators of Slick Aircraft Products Magneto equipped Lycoming Aircraft Engines This reprint is current at the time Service Letter No. L173C is issued. However, when complying with this Service Letter, insure that this reprint of Slick Aircraft Products Service Bulletin No. SB2-80C is still current at the time of...

January 6, 2005 Models Affected To all Owners and Operators of Lycoming IO-360-L2A, IO-540-AB1A5, IO-540- AC1A5, TIO-540-AJ1A and TIO-540-AK1A Engines Installed in Cessna Aircraft. As a product improvement an improved lower idle valve has been introduced into the fuel injectors used on IO-360-L2A, IO-540-AB1A5, IO-540-AC1A5, TIO-540-AJ1A and TIO-540-AK1A engines installed in Cessna Aircraft. This...

Supersedes Service Letter No. L180 A Models Affected To all Owners and Operators of Textron Lycoming Aircraft Engines Engines in aircraft that are flown only occasionally may not achieve normal service life because of corrosion. This occurs when moisture from the air and products of combustion combine to attack cylinder walls and bearing surfaces during periods when the aircraft is not used. The...

Supersedes Service Letter No. L197 January 19, 1988 Models Affected To all Owners and Operators of Textron Lycoming Piston Aircraft Engines In order to minimize valve sticking problems, procedures recommended in this Service Letter should be followed. Depending on the degree of intensity, sticking between the valve stem and guide can severely restrict the valve's opening and closing movements. A...

Supersedes Service Letter No. L192A January 19, 1988 Models Affected To all Owners and Operators of Lycoming Aircraft Engines. In many cases spark plug fouling resulting from the tetraethyl lead (TEL) in aviation fuels can be reduced or eliminated by proper operating techniques.

Supersedes Service Letter No. L185 A January 19, 1988 Models Affected To all Owners and Operators of Textron Lycoming Aircraft Engines We received many inquiries from the field expressing concern over the limited availability of 80/87 grade fuel and associated questions from use of higher leaded fuel in engines rated for grade 80/87 fuel. The leading fuel suppliers indicate that in some areas 80...

January 28, 1983 Models Affected To Owners and Operators of Lycoming Reciprocating Aircraft Engines. This Service Letter is to clarify Lycoming’s position on the fuel grades that are specified for use in our reciprocating engine models.

November 26,1971 Models Affected To all owners and operators of Avco Lycoming Aircraft Engines. As the use of spectrometric lubricating oil analysis has become more widespread in the field of general aviation, the problems of methods, procedures, schedules andinterpretation of data have become prevalent. This service letter is an attempt to clarify the subject and to define how lubricating oil...

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...