1976 Evinrude 40HP outboards Service Manual, Page 19Get this manual
DESCRIPTION FUEL FLOW
The fuel system consists of fuel tank, fuel pump, and carburetorThe fuel tank is non-pressurized, suction operatedA diaphragm-displacement type fuel pump on the motor draws fuel from the tank and furnishes it to the carburetor through fuel filter
The carburetor throat is frequently called the "barreL" Carburetors with single, double, or four barrels have individual metering jets, needle valves, throttle and Choke plates for each barrelThe two barrel carburetor is fed by single float and chamber while the four barrel model has separate float valve and chamber for each barrelINDUCED LOW VENTURI