Marvel Carbureter and Heat Control

The author wrote this book to teach the readers about carbureter and heat control and begins his treatise by introducing us to the construction that embodies the main body or mixing chamber and a conventional float chamber bowl with fuel strainer attached at the point of entrance of fuel to the bowl. Within the mixing chamber are two nozzles that proportion the amount of gasoline used in the mixture. One of these nozzles called the «low speed,» is regulated by the gasoline adjustment screw at bottom of carbureter and the other, called the «high speed,» is controlled by the automatic air valve. An air screw is provided which regulates the pressure of the air valve spring enclosed therein. Within this screw is also enclosed a plunger connected by a link to the air valve. The function of this plunger is to provide a resistance in addition to that of the air valve spring to assist in acceleration. This arrangement of plunger and air valve screw is termed the dash pot. A further control of the high speed jet is provided by the fuel metering valve operated by the carburetor throttle. This valve provides the maximum fuel feed to the «high speed» nozzle when the throttle is fully opened for high speeds and for quick «pick up.» During the ordinary driving ranges this valve controls the amount of fuel being used, thus providing all the economy possible. This valve is entirely automatic and requires no adjustment.