Abstract: A carburetion system wherein the choke opening is modulated in accordance with the ambient temperatures. A choke modulator mounted in the carburetion system's air cleaner employs a temperature sensitive provision to vary air flow to the choke thermostat and accordingly, varies the temperature at which the choke operates.The invention relates to improvements in carburetion systems.Carburetion systems wherein the choke opens too soon results in engine stalling. On the other hand if the choke remains closed or partially closed too long, the air-fuel mixture is too rich resulting in excessive undesired emissions, greater fuel consumption and even engine flooding.With the foregoing in mind, a new and different carburetion system is provided wherein the carburetor choke opening is modulated in accordance with ambient temperatures to obtain improved engine operation.