Service Procedures (Zenith 69)
Fuel Supply System (Zenith 69)
Accelerator Pump Circuit (Zenith 69)
The 69-series carburetor is of the single barrel updraft design, with double venturi, twin floats and a semi-concentric fuel bowl to permit operation at quite exteme angles without flooding or starving the engine. It is of the “sealed” and “balanced” type since all air for fuel bowl ventilation and idle operation must enter through the air cleaner. The fuel supply system is made up of a threaded fuel inlet fitting, fuel valve (needle and seat), float assembly and float chamber. The idle system consists of two idle discharge holes located in the side of the throttle body, idle jet, vacuum passage connecting the idle discharge holes with the idle jet, idle adjusting needle, idle air intake passage and an idle fuel passage.
The high speed system consists of a main and a secondary (small) venturi, discharge jet, main jet with variable adjustment, well vent jet and main dischrage jet. The accelerating system consists of a vacuum-controlled pump piston, a disc type check valve located at the bottom of the pump cylinder and an accelerating jet. The choke system includes a choke plate mounted on a shaft in the air intake and operated externally by a lever attached to the shaft.