1997 Johnson Evinrude "EU" 90 thru 115 90 CV Service Manual, P/N 507267, Page 57Get this manual
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 system
pump incorporates circuit that warns the operator The of "NO OIL" situation
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 circuits3Mixture 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 manifolds6718