If your engine was overhauled by Penn Yan Aero prior to November 2015, then Lycoming's Mandatory Service Bulletin 632 does not apply.
If your engine was overhauled by Penn Yan Aero after November 2015, please review the parts list supplied with your engine overhaul and determine if SL-13923A bushings were used. If so, your engine is not affected by Lycoming's Mandatory Service Bulletin 632 and no further action is required.
