Service Bulletin No. 583 A

Reprint of Mandatory Unison Service Bulletin No. SB2-08

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Supersedes Service Bulletin No. 583

July 21, 2008 

MODELS AFFECTED

All Lycoming new, overhauled, rebuilt, or repaired engines with: 

1. A Slick model 4300/6300 series magneto with a serial number beginning  with 0610#### through 0804####.

2. A LASAR model 4700/6700  series magneto  with a  serial number  beginning with 0610#### through 0804####.

3. Any magneto which  has had the cam, or the  cam as part of the contact  point assembly kit, replaced between October 1, 2006 and May 11, 2008.

TIME OF COMPLIANCE

Within  the  next 50  hours of engine  operation. Then at every 100 hours of engine operation or at annual inspection, whichever comes first.

Lycoming has learned that all new, overhauled, rebuilt, or repaired engines with a Unison Industries Slick  model 4300/6300 series or LASAR model 4700/6700 series magneto with the serial number range  listed  above may experience premature wear of the breaker point cam. Premature cam wear can cause excessive  timing drift which may lead to low magneto output power.

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