What was found
AFTER PRACTICING INSTRUMENT APPROACH AND GO AROUND, THE LT ENGINE THROTTLE LEVER STUCK AT 25" MAINFOLD PRESSURE AND 2500 RPM. AFTER DEPARTURE FROM AIRPORT CONTROL AREA, INSTRUCTOR PILOT WAS ABLE TO REDUCE LT THROTTLE DOWN TO 16-18" MANIFOLD PRESSURE AT 2500 RPM. AFTER DISCUSSION WITH FLIGHT DEPARTMENT PERSONELL IT WAS DESCIDED THE BEST COURSE OF ACTION WAS TO SHUTDOWN THE LT ENGINE AND PERFORM A SINGLE ENGINE APPROACH AND LANDING. AN EMERGENCY DECLARED AND LANDED UNEVENTFULLY. SINCE PREVIOUS INSTANCES OF PROBLEMS WITH ENGINE CONTROL CABLES IN THIS PARTICULAR MAKE AND MODEL AIRCRAFT, THE LT ENGINE THROTTLE CABLE WAS REPLACED AS PART OF A SCHEDULED PROGRESSIVE INSPECTION.