1995 Johnson Evinrude "EO" 60 LV 90, 115, 150, 150C, 175 Service Manual, P/N 503151, Page 55Get this manual
Description of Fuel System 1The 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 slow speed adjustable needlean intermediate air bleed orificeand high speed fuel orifice 2Fuel enters the vapor separation chamber through the fuel filterThe chamber allows fuel vapor to separate from the liquid fuelThe vapor is removed from the chamber by the operation of the float valve and vapor pumpThe operation of the float valve is controlled by the amount of fuel in the chamberThe chamber provides liquid fuel to the pump during start-up and operation
3The vapor pump is diaphragmdisplacement type, and is operated by changes in crankcase pressureThe vapor pump moves fuel vapor from the separation chamber to the air silencer
4The 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