What was found
ON DEPARTURE, CREW SMELLED FUMES AND SMOKE WAS PRESENT IN CABIN. CREW DECLARED AN EMERGENCY AND STARTED IMMEDIATE RETURN TO AIRPORT. MAINTENANCE EVALUATION FOUND OIL TANK LEVEL HIGH AND COMPLIED WITH DRAINING OF THE LH AND RH ENGINE UPPER OIL TANK TO A MORE APPROPRIATE LEVEL. SERVICED LH AND RH ENGINE OIL. PERFORMED ENGINE RUN AT TAKEOFF POWER BOTH LH AND RH ENGINES ALTERNATELY TO VERIFY NO SMOKE IN CABIN. NO SMOKE PRESENT IN CABIN AT TAKEOFF POWER. SUBSEQUENT FLIGHTS COMPLETED WITHOUT FURTHER ISSUE.