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mon-thurs 9-5 cst
The idle mixture controls the amount of fuel going through the idle port of the carburetor. You'll tune the idle fuel mixture with the idle speed screw to set the engine to idle rpm. The idle mixture screw is important to have when tuning the low side jet; otherwise, you may not get the engine to idle. Most EPA engines and carburetors do not have idle mixture screws to prevent adjustments to the carburetor.
Idle Mixture screw works with Tillotson PK carbs but not the Ruixing or most other clone carburetors.