What was found
ON TAXI OUT MEM, SMELLED A STRONG SMELL THEN A FULL MAIN DECK SMOKE WARNING WHICH LASTED FOR SEVERAL MINUTES. DECLARED EMERGENCY. DETECTION CLEARED ITSELF. RETURNED TO GATE. REPLACED NR 1 AND 2 PACK WATER SEPARATOR BAGS AS PRECAUTIONARY REF A310 AMM 21-51-16-3. BAGS DID NOT APPEAR VERY DIRTY. CLOSED ALL A/C DOORS AND RAN BOTH NR 1 AND 2 ENG AT IDLE FOR ABOUT 10 MINS WITH APU BLEED ISOLATED AND BOTH PACKS RUNNING. THERE WAS A STRONG ODOR THAT WAS NOTICED ALMOST INSTANTLY WHEN PACKS TURNED ON. RAN ENGINES AT HIGH POWER FOR EXTENDED PERIOD RAN PACKS AT SEVERAL DIFFERENT SETTINGS FROM HOT TO COLD ALL INDICATIONS NORMAL, NO ODOR OR SMOKE WAS NOTICED IN FLT DECK OR ON MAIN DECK OF AC.