a loss power in the right engine due to an excessively rich mixture that was the result of the pilot's failure to secure the priming control prior to takeoff. Also causal was the pilot's failure to follow the single engine procedures specified in the operating manual for this aircraft, and, his failure to attain and maintain the correct airspeeds for single engine operation, and to maintain directional control. A factor was the pilot's lack of total experience in multiengine aircraft.