What was found
(CAN) DURING TAXI THE LT FIRE WARNING LIGHT ILLUMINATED ON STEADY AND BURNING SMELL WAS DETECTED IN THE COCKPIT. THE LT ENGINE WAS SHUT DOWN AND THE FIRE WARNING LIGHT EXTINGUISHED APPROXIMATELY 30 SECONDS LATER.A SUBSEQUENT INSPECTION REVEALED THAT THERE WAS EXTENSIVE HEAT DAMAGE TO THE EXHAUST DUCT AND ASPIRATOR BUT A CURSORY INSPECTION OF THE ENGINES HOT SECTION REVEALED NO DAMAGE.THE ENGINE, ASPIRATOR AND EXHAUST DUCT WERE REPLACED AND THE AIRCRAFT RETURNED TO SERVICE. THE CAUSE OF THE OVERTEMP IS UNDETERMINED, PENDING AN ENGINE TEARDOWN.