GAS ENGINES 



497 



The essential parts of a simple carburetor are: bowl, 

 float, check valve, needle valve, and butterfly valve, or 

 throttle. The more elaborate types may have additional 

 parts, such as auxiliary air, preheater for air, preheater for 

 fuel, macerater to aid in mixing, and superheater. 



The carburetor universally used is the spray-nozzle or 

 atomizer type (Figs. 386, 387). In the beginning of the 



Priming lever 



Ffoof-ra/ye 

 spring 



Gajo/ine 

 chamber 



Hoar- 



float 



va/ve 



Gaso/ine 

 /hief-—.? 



fira/'n 



/Juxi/iary 

 air ra/ye 



rfir- a<//'vsfing 

 paii 



Venfuri fc/6e 



rf/r in/ef 



Fig. 387. A commercial carburetor of the spray-nozzle type (Stromberg) 



internal-combustion engine manufacture, a good quality of 

 fuel was available, engine speeds were slow, and little atten- 

 tion was paid to economy of operation. The carburetors 

 used were of the "surface" and "overflow" types. These 

 utilized but one of the principles of evaporation — expo- 

 sure of the fuel to a column of air. While these types are 

 no longer manufactured, the surface and overflow principles 

 are incorporated in many of the atomizer carburetors to 

 facilitate starting. The operation of the standard carbu- 

 retor is about as follows: A chamber is supplied with 

 gasoline which is maintained at a constant level by a float 



