1996 Johnson Evinrude "ED" 90 LV 125C, 130, 200, 225, 250 Service Manual, P/N 507128, Page 83Get this manual
2 Description of Fuel System
1The unit is combination mechanical fuel and oil pump, powered by crankcase pressure and vacuum pulses, which responds to various engine power settings by injecting the proper amount of oil into the fuel systemThe pump incorporates circuit of "NO OIL" situation
that warns the operator
[] 2The carburetors meter and distribute the fuel consumedThey control engine speed and power output by varying the intake charge densityTo react correctly to wide range of operating conditions, the carburetors have several separate fuel mixing circuitsCarburetor calibration is controlled by an adjustable idle mixture needlean intermediate air bleed orificeand high speed fuel orifice 3va engines are equipped with fuel manifold bypass valveAlthough normally closed, the pressure sensitive bypass valves can react to reduction in fuel pressureIf one pump output is reduced, the bypass valve will open and allow the other pump to supply fuel and oil to both manifoldsUnder some conditions, one pump might not be capable of maintaining sufficient fuel supply to provide full throttle operationHowever, part throttle operation should be available under most conditions[] 4Mixture enrichment for cold starting is controlled by fuel primer solenoidWhen activated at the key switch, the solenoid diverts some pump output directly to the intake manifolds5One OMC Electric Fuel Primer Pump Kit, PI 174651, is supplied with each va outboardWhen activated with springloaded, momentary switch, the pump fills the fuel distribution lines and engine fuel system for quicker startingYou must not use fuel primer bulb in V8 fuel system6V4 Commercial, V6, and va outboards are equipped with vacuum sensitive switch that sounds continuous tone of the warning horn if restrictions in the boat fuel supply system reach critical point