Carter YS Technical Help

The Carter YS carburetor is a single-barrel, side-draft carburetor produced by the Carter Carburetor Corporation, which was a major manufacturer of carburetors for various automotive brands from the 1920s through the 1980s.

The Carter YS carburetor was commonly used in military applications, specifically on the Willys MB and Ford GPW jeeps, which were used during World War II. These carburetors were designed for reliable operation under harsh conditions and are known for their durability and simplicity.

The Carter YS carburetor consists of several main components, including the throttle body, air horn, float, jets, and choke assembly. Fuel is drawn into the carburetor through the main jet, where it mixes with air in the venturi to create a combustible mixture. This mixture is then drawn into the engine through the throttle body, where the throttle plate controls the amount of air and fuel entering the engine. The choke assembly is used to restrict airflow during cold starts to provide a richer fuel mixture, allowing the engine to start and run more smoothly.

In summary, the Carter YS carburetor is a simple and reliable single-barrel carburetor that was widely used in military applications during World War II. Though not as common today, these carburetors can still be found on vintage vehicles and in restoration projects.

Float Adjustment

Remove top and turn it upside down allowing the float to rest on the needle & seat.

IMPORTANT: Do not put any pressure on the needle, as damage to the viton tip will cause flooding.

637S - 1/4", 950S - 9/64"

Measure the distance between the bottom of the float and the edge of the casting w/o the gasket. Don't have the carburetor number? Set it to 1/4".

Adjust the level by bending the tab in the center of the float arm. It is best to bend the tabs with the float off. Remove the float pin, adjust, then put it back on.

Float drop

Turn the top right side up. The float will hang about 45 degrees. It doesn't have to be exact. Just make sure the needle comes out enough to allow fuel to flow. Not so far out the needle gets bound up.

Test the needle & seat

Make sure the needle is sealing by letting the float rest on the needle (top upside down), and blow into the fuel inlet. If you suspect any leakage, wipe the viton tip with mineral spirits to clean off any residue.

Test the float

Heat up some water to just below boiling and immerse the float into the water. The hot water will heat up the inside of the float and if there are any leaks, bubbles will come out of the hole.

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