I have a carter afb that has an unusual choke setup. It has the bi metal spring that opens the choke when heated, but it has no provision for a heat riser and its not electric. It does have a vacuum tap. I thought maybe they ran the vacuum supply thru a ported vacuum switch and used that to pull the piston down to operate the choke, but thought better of that when I discovered that the tap is a vacuum source. So what is the heat source for this choke? The number is C3 9637 S. I believe that's from a early 60's ford. Trying to figure out how to make this choke work properly with the 302 I want to put is on. I could switch to a electric conversion, just trying to save a bit if possible.
The air source for the hot air chokes usually goes into the housing, not the coil cover. If there are no provisions for hot air, this MIGHT be a hot water setup. I've seen early 1960s cars where there was a clip that held the heater hose against the choke coil to provide heat. Some GMs actually had a water hose connections to the choke coil cover itself.
Until 1966, GM carburetors had a choke heat tube (not a vacuum tube) plumbed from the bi-metal spring housing on the carburetor to the heat cross-over in the intake manifold or to the exhaust manifold. In order to use that that type choke arrangement, Pontiacs required a OE intake manifold that had a choke heat tube inside the heat crossover. For example: I converted my 1963 Pontiac tri-power center carburetor to an electric coke because I foolishly blocked the heat crossover ports in the heads with aluminum in order to get a cooler fuel mixture...big mistake. I first tried gaskets with blocked heat ports but they would last about 100 miles before they were burned through. After blocking the heat ports with molten aluminum, I had to install a electric choke kit on the center carburetor because the engine would not start without a choke! With a blocked heat crossover, the damned carburetor never got up to operating temperature and the engine ran rough and idled erratic when the weather was below 40 degrees. I learn the hard way that no carburetor heat is for racing only.
The 1966 and later GM intake manifolds were equipped with a heat coil inside a choke stove that was mounted on the heat crossover and linkage from the heat coil that opens and closes the choke plate in the carburetor. It was found that the choke heat tube inside the manifold would burn out. Early Chevrolet used a heat tube from the choke housing bi-metal spring on the carburetor to the exhaust manifold.
Before Edelbrock put the Performer brand on the Carter Competition Series AFB here is the info on the numbers,the Carter 9635SA(GM linkage,Chevy) is like the Performer 1406 except the 1406 is jetted leaner for emissions and both have electric chokes.The 9637S and 9627S have Ford linkage,the 9636S has Mopar linkage.Someone has "Mickey Moused" your AFB it should have an electric choke like mine: Carter AFB 625 CFM Ford linkage Model 9637S All 9635,9636 & 9637 are electric choke.Edelbrock Performers used the 9635 style linkage and sell bolt-on kits to adapt to Fords and Mopars.You could buy my Carb which is correct or buy a new Edelbrock electric choke :Edelbrock Electric Choke Kits 1478 - SummitRacing.com
Here's a picture of the choke set up. The port under the thermostat has vacuum when the engine is running. There is a bleed port off of this that goes back to the piston that pulls the choke linkage. I'm really stumped on this one.
It looks like someone probably broke the original choke cover and replaced it with the older style non-electric buy this: CARTER ELECTRIC CHOKE KIT FOR AFB 4 bbl CARBURETOR with HOT AIR CHOKE | eBay the small port under the choke can be blocked off take a good look at the picture below,this is how your choke should look.As I stated above ALL 9600 series Carters are electric choke.
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