If your lawnmower will start and run with the choke on but dies when the choke is turned off, it may have a problem with the carburetor. The carburetor brings air and fuel together and mixes them in the perfect ratio for combustion before they enter the engine. There are several passages in the carburetor that allow fuel to enter the air stream depending how the throttle is set. The idle circuit, for when the throttle is nearly closed and the engine is idling. The transition circuit, for when the throttle is transitioning from idle to full. The main jet is used when the throttle is at full. The choke assists with providing additional fuel when the engine is first started. When closed, the choke plate restricts most of the incoming air from entering the carburetor’s venturi. This creates additional low pressure in the venturi and also forces air to... If your lawnmower will start and run with the choke on but dies when the choke is turned off, it may have a problem with the carburetor....
