The function of the centrifugal adjustment device is to increase the ignition advance angle with the increase of the speed of the gasoline engine. The support plate is installed on the distributor shaft. A spring is installed between the small end of the block and the support plate, so that the weight is in a closed position. The lower end of the breaker cam is an empty sleeve, which is on the shaft. There is a dial plate with long holes under the casing, which is sleeved on the pins of the two heavy blocks. When the speed of the gasoline engine increases, the two weights overcome the elastic force of the spring under the action of centrifugal force, and expand outward with the pin shaft as the center. Some open the breaker contacts, which increases the spark advance angle. Conversely, the ignition advance angle is reduced when the rotational speed decreases. Because the optimal ignition advance angle and rotational speed are not linear. Therefore, some measures are often taken to improve the characteristics of the centrifugal adjuster, such as using two springs with different thicknesses. The thick spring has a certain clearance, and only the soft spring works when the speed is low. When the speed rises to a certain level, the two springs work together. When the rotation speed is further increased, the ignition advance angle no longer increases with the rotation speed when the pin rests on the outer edge of the dial hole.