What was found
DURING ENG #1 START, MM INDICATION BEGAN TO MOVE PAST 77% REACHING THE MM EXCEEDANCE ONCE THE ENG REACHED IDLE. A TEST FLIGHT EVAL FOUND DURING TWO CONSECUTIVE STARTS OF #1 ENG; MAST MOMENT GAVE 3-4 AND 2 ERRONEOUS DEVIATIONS ABOVE 90%. ADDITIONAL 2 DEVIATIONS OCCURED DURING COAST DOWN OF THE ROTOR AFTER THE 2ND START. MM INDICATIONS WERE NORMAL (2-6%) AT GROUND IDLE THROUGH 70% TORQUE SINGLE ENGINE. AFTER SHUTDOWN MM EXCEEDANCE INDICATED: FLT # 20 MM > 64% 4.4S 111.1% MM> 77% 2.6S 111.1%. REMOVED AND REPLACED SSTU IAW AMM 63-42-00, 4-2.