What was found
UPON ADVANCING POWER FOR TAKEOFF, FELT A RUMBLING IN THE RUDDER PEDALS. ABORTED T/O AT AT 10 KTS. TURNED OFF RUNWAY, ANOTHER ACFT ADVISED SEEING FLAMES FROM THE NR 2 ENGINE. SHUTDOWN ENGINE, BLEW BOTH FIRE BOTTLES. REMOVED NR 2 ENG PER WORK CARD 71T1101. INSTALLED NR 2 ENGINE IAW WORK CARDS 71T1701, 7110000-00-94, 53T5901, 53T5001, 7110000-00-91.