We have 4 different types of chokes, Intregal (or integrated), Divorced, Electric & Electric Conversion Kits.
You can find listings for OE style chokes and conversion kits by make and model in the catalog here.
The integral choke is mounted on the carburetor itself. either off the side of the bowl or throttle body. The illustration below shows the choke mounted on the top of the carburetor. The thermostat is heated by a heat tube that runs down to the exhaust manifold. The heat tubes heats up the thermostat and moves the choke valve to the open position. A vacuum passage in the carburetor feeds up to the choke housing and helps pull in the heat from the heat tube. Some of these chokes will also have a hot water jacket running through, or on the thermostat to facilitate heating.
With this type of choke, the choke is not opened by the thermostat. For the most part when warm, the choke opens from the weight of the linkage hooked to it. Along with that, the vacuum from inside the carburetor pulls it open.
These images show some various carb types with integrated chokes. Your carburetor will have a bimetal choke housing with either a metal cap/coil or a black plastic cap/coil. These heat style integrated chokes use a tube which transfers heat from the manifold to the choke housing through a port similar to those in the below images. As the carb heats, the coil inside the housing relaxes, allowing the choke flap to spring open, letting more air into the carburetor.
One of the number one issues we run into is damaged, broken, rotted, rusted heat tubes and manifold ports. The tubes are not available aftermarket that we’ve been able to source consistantly, and we typically recommend installing an electric choke conversion kit at this point.
The divorced choke type has the thermostat mounted in the intake manifold instead of on the carburetor. In this illustration, the arrow points to the thermostat which is covered by a metal shield. A rod connects the thermostat to the choke lever, which controls the choke valve to be opened, or closed. As the intake manifold heats up, the thermostat coil expands, opening the choke valve.
The part you can’t see under the shield would look something like this:
This is a typical electric choke mounted on the carburetor, which is integrated (metal housing on the carburetor body itself). In this case there is one wire on the choke thermostat. This is the 12v source, which all electric chokes use. The thermostat is grounded via the carburetor itself. Some electric chokes will have a 2nd wire (ground wire), which is connected back to the carburetor. When the key is on the thermostat is heated up, opening the choke valve. Many later model carburetors came with electric chokes stock, and we do sell replacements for them. This style would not have an open port on the side of the housing for heat transfer. You can see on the left side of this image the port, which is capped off.
Electric choke thermostats need 12v power. Less may work, but the choke will open slower than it should. 6v does not work. Use any 12v source that is hot only when the key is turned on.
Putting a fuse in line with the thermostat is OK, but the thermostat will work without one.
No resister should be used in line with the thermostat.