What was found
ON CLIMB OUT BOTH PILOTS OBSERVED AN ENGINE SURGING SOUND, ITT DEG. C ON ENGINE 1 NOTICED APPROX 100 LOWER IN COMPARISON TO ENGINE 2. FUEL FLOW ON ENGINE 1 WAS HIGHER THROUGHOUT THE FLIGHT. REMOVED FROM SERVICE. REMOVED AND REPLACED #1 PROPELLER CONTROL UNIT, OVERSPEED GOVERNOR, FEATHER PUMP AND CLEANED CONNECTORS ON #1 PEC. C/W POWER ASSURANCE RUNS ON #1 AND #2 ENGINES. POWER ASSURANCE CHECKS GOOD. ALL OPERATIONAL CHECKS GOOD. NO SURGING ON #1 ENGINE. NO FURTHER DEFECTS NOTED. AIRCRAFT RETURNED TO SERVICE.