What was found
PDX FLIGHT 2139 - NR 1 ENGINE FAILED TO LIGHT OFF, RAMP REPORTED LOTS OF WHITE SMOKE COMING FROM REAR OF NACELLE. SMELL OF FUEL INSIDE AND OUTSIDE DURING START ATTEMPT. RAN START ABORT CHECKLIST. CAUSE UNKNOWN. MAINTENANCE INSPECTED, FOUND AUTO RELIGHT SWITCHES TO BE STICKING. OPERATED NR 1 POWER LEVER THROUGH FULL TRAVEL. STARTED NR 1 ENGINE SEVERAL TIMES IN AUTO POSITION. AIRCRAFT OPERATED NORMALLY IN ALL STARTS. NO PARTS REPLACED. AIRCRAFT RETURNED TO SERVICE.