Service Letter No. 197 A

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 sticking valve condition is often identified by an intermittent hesitation, or miss, in engine speed.