Pontiac 1953 Owners Service Manual page 45

As you prooobly know, a fuel-air mixture which contains a large
proportion of gasoline is called a "rich" mixture. One that contains
relatively little gas is called "lean" mixture. The proper richness or
leanness of the mixture depends not only on the speed of the engine,
but also on the temperature of the engine. The carburetor takes care
of the former- automatic choke takes care of the latter.
The choke controls the choking of your engine automatically-
better than even the most expert driver could do with the old-style
hand equipment. A thermostatic arrangement lets the temperature
of the air under the hood control the richness of the mixture. A
linkage is also provided which is connected with the carburetor
throttle and causes the engine to operate in "fast idle" during the
warm-up period.
As the engine warms up, richness is decreased. When normal
operating temperature is reached, the choking mechanism auto-
matically shuts off and engine slows down to the proper idle speed.
A carburetor is like a man's appendix;
it
gets blamed for every-
thing. It takes the blame for hard starting, slow pick-up, poor accel-
eration, balky engine or low gas mileage. The trouble can be in the
carburetor, of course, but all these symptoms can also be caused by
irregularities in the ignition or compression systems.
The checks made on the carburetion system will show what
adjustments, if
any, are needed.
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