What was found
ENGINE WAS REMOVED FOR INTERNAL VIBRATION AND REPAIRED BY MFG. REPLACED CRANKSHAFT ENGINE, REINSTALLED IN ACFT. AFTER APPROXIMATELY 16 CYCLES, THE STARTER WAS ENGAGED WITHOUT ENGINE TURNING. REMOVED STARTER ADAPTOR, P/N 643259A18. INSPECTED AND FOUND CLUTCH SPRING BROKEN, 5.3 HRS IN SERVICE.