What was found
DURING CRUISE FLIGHT PILOT REPORTEDLY TRIED TO REDUCE POWER TO IDLE, WAS UNABLE, RETURNED TO HOMEBASE AND LANDED UNEVENTFULLY USING MIXTURE IDLE CUT-OFF. UPON INSP OF THROTTLE LINKAGE IT WAS DISCOVERED SPLINES ON THROTTLE LEVER AND SHAFT WORN. IT IS SPECULATED THAT THE LEVER WAS INSTALLED ON SHAFT WITH SPLINES MISALIGNED, AFTER AN UNDETERMINED AMOUNT OF TIME SPLINES MAY HAVE REALIGNED THEMSELVES BUT WITH SOME `PLAY` IN ACTUATION, CAUSING ADDITIONAL WEAR TO CONTINUE UNTIL SUCH TIME LEVER WOULD ROTATE ON SHAFT WITHOUT ROTATING LEVER. ORIGINALLY MFG HAD "NO" SPLINES ON LEVER, BUT LEVER WAS MADE FROM A SOFTER MATERIAL , IE BRONZE, ALLOWING IT TO "SET" IN PLACE ON SS, THROTTLE SHAFT.