What was found
AFTER LANDING ON SS169C, MOVED ENGINE THROTTLES TO GROUND IDLE WHILE LOADING AND UNLOADING PASSENGERS. WHEN THROTTLES MOVED BACK TO FLY, NR 2 THROTTLE MADE A NOTICEABLE CLICK AT THE FULL OPEN POSITION AND TRAVEL FURTHER FORWARD IN THE QUADRANT. PULLED THROTTLE BACK SLIGHTLY, RPM RESPONDED. RETURNED THROTTLE TO FULL OPEN. CAREFULLY LIFTED TO A HOVER AND POWER SEEMED NORMAL. UPON TAKEOFF, NR 2 ENG WOULD NOT PRODUCE MORE THAN 75 PERCENT TORQUE WHILE NR 1 WOULD INCREASE TO 100 PERCENT. WHEN COLLECTIVE REDUCED, NR 2 ENG REMAINED AT 75 PERCENT TORQUE. RETURNED TO ICY, MADE A SLOW RUN-ON LANDING. WHEN NR 2 ENGINE LEVER RETARDED TO IDLE, WORKED NORMAL, HOWEVER ENGINE RPM WOULD NOT GO BACK TO FLY WHEN ADVANCED.