Abstract: Trim control of a partial oxidation gas generator for the production of synthesis gas, reducing gas, or fuel gas is effected by two improved control schemes which are automatically operated separately or in sequence. The control systems include sensors sensing the flow rate of the feedstreams and analyzers which provide signals corresponding to the wt. % carbon in the effluent gas quench cooling and scrubbing water for use in controlling the particulate carbon in the effluent gas stream, and/or signals corresponding to the mole fractions of CO.sub.2, CH.sub.4, CO and H.sub.2 (dry basis) in the cooled and cleaned effluent gas stream for use in controlling the temperature in the reaction zone.