What was found
ON ENGINE START NR 2 AFTER START LEVER RAISED TO IDLE, MASTER CAUTION LIGHT OVERHEAT/DETECTOR AND ENGINE 2 OVERHEAT LIGHT ON FIRE PANEL ILLUMINATED. SHUTDOWN NR 2 ENGINE PRIOR TO STARTER CUTOUT. CONTINUED MOTORING ENGINE FOR 3 MINUTES, ESTIMATED, NR 2 FIRE LIGHT ILLUMINATED. PULLED & ROTATED FIRE HANDLE AND DISCHARGED BOTTLE. LIGHT WENT OUT, LESS THAN 30 SECONDS LATER FIRE HANDLE ILLUMINATED AGAIN. ROTATED HANDLE TO SECOND BOTTLE, DISCHARGED NORMALLY. FIRE LIGHT EXTINGUISHED. ENGINE 2 OVERHEAT LIGHT REMAINED ILLUMINATED FOR MORE THAN 20 MINUTES. ACFT GROUNDED. ACCOMPLISHED AMM TASK 71-00-00-800-803-F00 INSP AFTER AN ENGINE FIRE, USE OF FIRE EXTINGUISHER AGENTS. NO DEFECTS NOTED. PERFORMED DRY MOTOR OF NR 2 ENGINE REF AMM 71-00-00. R & R BOTH FIRE BOTTLES T/C 78126000. REF L/P 11604697, ACCOMPLISHED ENGINE/APU FIRE DETECTION BITE REF FIM 26-10, TASK 801, TEST PASSED. ACCOMPLISHED NR 2 ENGINE WIRING HARNESS/FIRE DETECTOR FAULT ISOLATION REF FIM 26-10, TASK 805, ALL VALUES WITHIN LIMITS. R & R MW0326 & MW0325 REF AMM 26-11-02, OPS CHECK NORMAL. R & R NR 2 ENGINE LT AND RT CORE DETECTOR ASSEMBLIES REF AMM 26-11-01, OPS CHECK NORMAL. R & R MW0315 FAN FIRE DETECTION HARNESS REF AMM 26-11-02, OPS CHECK NORMAL. NR 2 ENGINE FIRE OVERHEAT LIGHT STILL ILLUMINATES DURING START. R & R ENGINE AND APU FIRE DETECTION MODULE, REF AMM 26-10-01, NO HELP, INSTALLED ORIGINAL UNIT, OPS CHECK NORMAL, NR 2 OVERHEAT LIGHT.