1993 Johnson Evinrude "ET" 90 degrees CV Service Manual, P/N 508285, Page 54Get this manual
Description of Fuel System f211The 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 systempump incorporates circuit that warns the operator The of "no oil" situationf312The carburetors meter and distribute the fuel consumed They 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 circuits