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are like a central power house with the battery as an electrical storage
tank. From the generator some of the main feed wires go to the dis-
tributor, which can be thought of as the central switchboard of the
ignition system because it intermittently and automatically connects
each spark plug with the electrical current so that ignition of the
charge in the cylinder occurs at exactly the right time. Other feed
wires go to the lights, horns, and electrical
accessories.
The tests on the electrical system check each
of
the three electrical
circuits; the starting, the ignition, and the charging circuits.
Carburetion-Carburetion is the automatic mixing of gasoline with
air in the proper proportions at all engine speeds and temperatures.
This is done by the carburetor and the built-in automatic choke.
In the carburetor all the openings through which fuel and air travel
are fixed, excepting the idling jets which are controlled by the idling
adjusting screws. All other
·
mixtures of gasoline and air are auto-
matically controlled in relation to the needs of the
engine.
As you probably know, a fuel-air mixture which contains a large
proportion of gasoline is called a "rich" mixture. One that contains
relatively little gasoline is .called a "lean" mixture. The proper rich-
ness 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. 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
~
'c
to operate in
"fast idle"
during the warm-up period. The fast idle
system is designed to enable the engine to start and idle without
stalling even at below zero temperatures. Therefore, when the car is
started as instructed on pages 12 or 16 during more moderate tem-
perature conditions the initial idle speed may seem high. If this is
the case after engine starts open accelerator slightly and then release.
This will reposition the throttle setting from the
"starting"
step of
the fast idle cam to the
"running"
step and give a slower idle speed.
As
the·
engine warms up, richness is
decreased.
When normal operating
temperature is reached, the choking mechanism automatically shuts
off and engine slows down to the proper idle speed.
The checks made by your Pontiac dealer on the carburetion system
·
will show what adjustments, if any, are needed.
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