D Series Master Controls The D Series Master Control provides positive fuel shutoff (complete shutdown) with manual override at the control to allow the operator to manually override the valve each time the engine is started. Specifications: Primary oil setting: 5 to 25 PSI (as required and specified) Standard fuel flow coefficient (CV): approx. 2.85 GPM (10.7 LPM) diesel powered units Fuel inlet/outlet port: 3/8 NPT 1 Includes #41737 check valve (1/4 ) for fuel return line. Master Control Mounting Bracket: Order Part Number MB-1.