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Cold Start
1962 Dodge Dart 330, 392 Hemi, T56 6 speed manual.
1986 GMC K1500 Jimmy, 396 V8, 700R4, 208C, 4x4.
IHC in the early to mid-fifties.
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Smog_guy wrote:That's what the choke is for, cold starts.
If you remove the aircleaner you should see it on top.
It's operated by a cable on old vehicles (say pre-1960).
You want to hook it back up or address the cable binding issue or whatever.
A good place to start is to just see if you can move the choke open and closed with your fingers.
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Buzzman72 wrote:The choke does NOTHING to put gas into the carb. It simply restricts the amount of air going into the carb, resulting in a slightly richer fuel/air mixture. Pumping the gas only TEMPORARILY adds more fuel to the engine, as the carburetor's accelerator pump comes into play; when that temporary shot of fuel is run through the cylinder and exhausted, it's gone.
On cars and trucks that have slightly newer carburetors than our trucks, they have automatic chokes. To set an automatic choke to run, press the accelerator pedal to the floor ONCE and release. Besides adding a shot of fuel from the accelerator pump, this also brings the "fast-idle" cam on the carburetor into play. The fast-idle cam is connected to the automatic choke, and it prevents the throttle blade[s] on the carb from completely closing until the choke releases. These old trucks with manual chokes DO NOT HAVE a fast-idle cam on the carb; that's what the 'THROTTLE' knob is used for.
Physics class taught us that cold air is more dense than warm air. So for the fuel/air mixture to be stoichiometrically correct on a cold engine, more fuel must enter the engine, relative to the amount of air coming in. Otherwise, a lean fuel/air mix enters the engine, and the engine tends to "spit back" through the carb on acceleration.
There's a lot more to the subject than that, with the heat riser in the exhaust manifold coming into play as the engine warms up...but you first should understand how the carburetor functions before you can move on from there. It's not rocket science, but it IS science...mostly basic grade-school and high-school physics.
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