Carter UT Universal Tractor

Low Speed Circuit

Fuel for idle and low speed operation is drawn from the fuel bowl (A), through fuel passage (B), past main metering jet (C), up channel and through idle jet (D) and is mixed with air from idle air bleed (E). This relatively rich mixture passes through the economizer (F). Part of it then passes into the carburetor bore through idle port (G) and the balance enters the bore past the idle adjustment screw (H). Clockwise rotation of the idle adjustment screw, which controls the amount of uel air mixture, leans the mixture, while turning the screw counterclockwise richens it. Do not attettempt to remove the idle air bleed (E) and economizer (F).

High Speed Circuit

The main metering jet (C) supplies the amount of fuel required for high speed operation. As the carburetor throttle valve (J) is opened (beyond idle speed requirements), high velocity air passing through the carburetor throat creates a suction at the main nozzle outlet. This causes fuel to flow from the fuel bowl, through main metering jet (C) where it mixes with air from the nozzle bleed (K). This fuel air mixture passes through main nozzle (L) and into the air stream at the carburetor throat. Clockwise adjustment of the main metering screw (M), which controls the amount of fuel, leans the mixture. Maximum mixture is usually obtained with three turns open. Do not attempt to remove nozzle bleed (K).