October 30, 2015
All O-360-A4A and -A4J series engines with serial number up to and including L-23659-36A, IO-360-B4A series engines with serial number up to and including L-17977-51A (not installed on Piper PA28-181 (Archer III) aircraft) and rebuilt engines shipped prior to August 17, 1977 are subject to this modification. Also, any O-360 model converted to O-360-A4A or -A4J must comply with this Service Bulletin. All O-360-A3A engines installed in Avions Pierre Robin aircraft with serial numbers up to and including L-32684-36A and any rebuilt or overhauled engines ordered for Avions Pierre Robin aircraft and shipped prior to December 1, 1990 must comply with this Service Bulletin. All O-360-A3A engines installed in Avions Pierre Robin Aircraft with serial number L-32685-36A and up and any rebuilt or overhauled engines ordered for Avions Pierre Robin Aircraft and shipped after December 1, 1990 are in compliance with this Service Bulletin.
TIME OF COMPLIANCE
Within the next 100 hours of engine operation, or at annual inspection, whichever occurs first.
REASON FOR REVISION
Qualified applicability for IO-360-B4A engines not installed in Piper PA28- 181 (Archer III) aircraft.
IO-360-B4A engines (not installed on Piper PA28-181 (Archer III) aircraft) and O-360-A4A, -A4J, and - A3A engines are built with a crankshaft designed to match the operating characteristics of the propeller. This combination, by effecting efficient power transfer, provides satisfactory performance of the aircraft. However, service records of aircraft with this engine and propeller combination indicate requirement for more than usual maintenance of the right hand magneto drive components.
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