Carburetor - HITACHI 2-Bbl: Description

Carburetor is a 2-barrel downdraft design with primary and secondary throttle system. A choke valve and idle circuit are used in primary system only. Both primary and secondary venturis have main fuel nozzles.

A mechanical accelerator pump and vacuum operated power valve are used for increased fuel requirements. An anti-dieseling switch or solenoid valve is used to stop fuel flow in idle circuit (on some models) when ignition switch is turned off. Federal Nissan models use a cold enricher system; other models use an electric controlled automatic choke.

Some models use an altitude compensator device to maintain optimum air/fuel ratio at higher altitudes. Nissan uses a mixture control solenoid control valve in conjunction with ECC (Electronic-Controlled Carburetors) on California models. Federal models use an idle speed control actuator.

Some carburetor models may also include dashpots, throttle positioners, vacuum break diaphragms, bowl vent solenoid valves, and other specialized devices.