The old GL8 engine hummed.

The old GL8 engine sounded for the following reasons:

1. The air filter is dirty. Air filters are designed to protect the engine and reduce wear. Generally, it is replaced around 1 10,000 km. If it is not replaced in time, the engine will have low idle speed due to insufficient air intake, resulting in abnormal noise.

2. The high-voltage line is broken, indicating that the conductor core of the high-voltage line is broken, which will affect the ignition and cause abnormal engine sound;

3. Life of spark plug. Spark plugs have a life. After exceeding 30,000-40,000 kilometers, the ignition efficiency is obviously reduced, resulting in abnormal engine noise;

4. Carbon deposit and oil dirt are blocked. Throttle, idle valve and air intake will be blocked by carbon deposit and oil dirt after a period of use, which will affect the stability of idle speed and cause abnormal noise of the engine.