Which method is typically used to adjust idle speed on a float-type carburetor?

The method used to adjust idle speed on a float-type carburetor is through the eccentric screw adjustment. This screw is usually part of the carburetor's structure and, when turned, alters the position of the throttle plate or the airflow through the carburetor. By doing so, it precisely adjusts the idle speed of the engine without affecting other aspects of the air-fuel mixture.

Eccentric screws provide a straightforward mechanical way to achieve the desired idle speed, allowing for a more direct manipulation of the throttle opening. This type of adjustment is crucial for ensuring that the engine runs smoothly at idle and can be finely tuned based on the specific performance requirements of the engine.

Other methods, such as throttle linkage adjustment, do affect the way the throttle responds but are not primarily intended for idle speed adjustments. Electronic sensor calibration pertains to modern fuel injection systems rather than traditional float-type carburetors. Fuel gauge setting, meanwhile, is irrelevant to idle speed as it deals with fuel level indicators rather than engine performance at idle.