What was found
AFTER LANDING, DURING TAXI , PROPS DIDN'T SEEM TO COME OUT OF FLT IDLE TO DISC FOR A MINIMUM OF 20 SECS, POSSIBLY LONGER. ACFT TAXIED AT FASTER THAN NORMAL SPEED & ACCELERATED IF BRAKES WERE NOT APPLIED WITH POWER LEVERS IN DISC POSITION. AFTER 20 OR MORE SECONDS, PROPS FINALLY ATTAINED DISC POSITION. NOISE CHANGE INDICATION ONLY. PSEU & CDS SHOW NO RELATED FAULTS. GROUND RUN IN & OUT OF FEATHER, COULD NOT DUPLICATE DISCREPANCY. REPLACED PEC NR 2 AS A PRECAUTIONARY MEASURE IAW AMM 61-20-36-000-801 & 61-20-36-400-801. OPS TESTED GOOD. RETURNED TO SERVICE.