Service Bulletin No. 584 B

October 17, 2008

MODELS AFFECTED

All Lycoming new, overhauled, rebuilt, or repaired engines with: 1. A Slick model 4200/4300/6200/6300 series magneto with a serial number beginning with 0409#### through 08080453. 2. A LASAR model 4700/6700 series magneto with a serial number beginning with 0409#### through 08080453. 3. Any magneto which has had the carbon brush or distributor block assembly replaced with components packaged between September 1, 2004 and August 14, 2008.

NOTE: The magneto model number and serial number can be found on the magneto identification plate.

TIME OF COMPLIANCE

At the first 25 hours of engine operation, then at 500 hours of engine operation, or at annual inspection; whichever occurs first, until terminating action is accomplished.

Lycoming has learned that all new, overhaul, rebuilt, or repaired engines with a Unison Industries Slick model 4200/4300/6200/6300 series or LASAR model 4700/6700 series magneto with the serial number range listed above may experience premature carbon brush wear. Premature brush wear can lead to failure of the magneto to provide a consistent spark and may cause loss of engine power.