3. The Carburettor, Choke Operation

This is the Front of the carb, with the throttle fully open and the choke off. The oval-ish paddle above the main airway lowers when you raise the arm, here on the right of the picture, creating a restriction to the air flow, so enriching the fuel-air mixture.




Here we can see the front of the carb with the choke lever up, so the choke is 'on'. The small hole in the paddle allows some air to flow, but the restriction increases the amount of fuel in the air-fuel mix, so helping the motor to start in certain circumstances.