MECHANIC STATED HE WENT TO TOP OFF THE RADIATOR COOLANT, HE TOPPED IT OFF & INSTRUCTED THE OPERATOR TO START THE ENGINE. ENGINE WOULDN'T START, SO HE CONNECTED JUMPER CABLES TO THE STARTER, ST ILL WOULDN'T START. WENT TO CAB AREA & SPOKE WITH OPERATOR. OPERATOR REPORTED THE SMELL OF SMOKE. MECHANIC FOUND FLAMES FROM FUEL PUMP & EMC AREA. HE EXTINGUISHED FLAMES WITH HAND HELD UNIT F