choke thermostat

72fbird · 10-20-2004, 10:05 PM

Does any one know what a choke thermostat does? and where is it located on a 350 2bbl engine?

FormulaLT1 · 10-21-2004, 03:26 AM

Its explained in that article I sent you in the other thread and thats a good read , So I would read that before hand. I would copy and paste but it would take up the first page here just by itself.

72fbird · 10-21-2004, 05:41 AM

wait i looked on that page and didnt see anything on it? is it actually in the article or do i need to click a sub link to it?

FormulaLT1 · 10-21-2004, 06:11 AM

Taken from the article re-read the part about Thermostic style (I know it doesn't use the word specific but this just a easy basic's article that is just a good quick reference .)

THE CHOKE SYSTEM
Most aftermarket carburetors do not have a full choke plate. Instead, a machined groove or passage allows air to pass when the butterfly is closed. These styles usually offer no adjustment beyond the thermostatic (heat-activated) spring tension and fast idle. Spring tension is adjusted by rotating the spring housing. This alters the spring tension, changing the time required for the spring to heat up, uncoil, and open the choke. Factory-style carburetors usually have similar settings, but also feature a full choke plate that closes off all air when shut. This requires a vacuum-operated choke pull-off. As soon as the engine starts, the fast idle speed causes the choke plate to blow open a small amount, and it will be further opened with the vacuum break. The effect the pull-off has over the opening is usually adjustable, and is responsible for a clean fast idle with no loading.
PHR Tuning Tip: Fast idle speed is critical to both styles of choke plate. When a pull-off is used, set the fast idle to specifications before making any adjustments

Gunstar1 · 10-23-2004, 10:22 AM

Quote:

Originally Posted by 72fbird

Does any one know what a choke thermostat does? and where is it located on a 350 2bbl engine?

A choke thermostat controls the idle of the car by controlling the opening of the butterfly on the top of the carb. This allows more or less air to flow into the engine depending upon the operating temperature of the engine.

The choke is sensitive to heat produced by the engine.

If the two barrel carb on the 72 350 is the same as it is for the 74 350, it's the black disc on the passenger side of the carb. It's held in place by three screws and small metal plates. It can be adjusted by losening (not removing) the three screws and then be turned with the large slot (like that of a flathead screw) in the center of the black disc.

Some carbs have the choke coil mounted directly on the intake manifold. It is covered by a small metal housing that is screwed to the manifold. This is also located on the passenger side of the engine, next to the carb. It will have a small metal rod coming out of it and going up to the top butterfly of the carb. This type is adjusted by bending the metal rod that comes out of it.

Both types can wear out over time due to the constant changing of the heat applied to them. You can get them at your local parts place.

72fbird · 10-23-2004, 12:35 PM

yea i have looked at the prices of them....thanks i have been trying to figure out what that was yea there is a small metal box on the passenger side of the carb. and then a wire going from that box to the carb. but there is no tension on the wire like there is suppose to be....why?

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