416 



FARM MOTORS 



the market. Practically all of these devices depend upon the 

 liquid fuel being caught by the incoming air and atomized on 

 its way to the cylinder. Fig. 302 illustrates the principle of 

 the carburetor. Gasoline flows into the chamber A ; air 

 enters at B and passes through the chamber C into the en- 

 gine cylinders. As the air passes the tube D it takes up the 

 charge of gasoline which has been admitted through the nee- 

 dle valve E, and carries it on into the engine with itself. 

 Since the air passes the tube D at a velocity of about 6,000 

 feet a minute, it immediately atomizes the gasoline and forms 

 it into a gas. I r ig. 303 is a commercial carburetor wherein 



the gasoline is kept at a 

 constant level in the reser- 

 voir. Fig. 304 shows a 

 float-feed carburetor, the 

 principle of which is illus- 

 trated in Fig. 305. As fast 

 as gasoline is taken from 

 the tube A the float B 

 drops and more gasoline 



enters the reservoir C. 



The charge of gasoline 

 taken into the engine each 

 time is so small that the 

 amount can be regulated 

 only by a needle valve. 

 Such valves as are used 

 about the pump are far 



PJG. 303-CONSTANT-LEVEL CARBURETOR ^ ^ ^ ;,, ^ ^ 



to this minuteness of the charge that the gasoline has to be 

 kept at a constant level in the reservoir of the carburetors. 

 For instance, if the carburetor illustrated in Fig. 303 has no 

 overflow, but the attendant endeavors to regulate the amount 

 of gasoline in the reservoir by means of the valve in 



