What are the symptoms of valve leakage?

[StLilliana]

Symptoms of valve leakage: 1. It will cause insufficient power and slow acceleration; 2. The engine sound is very scattered, and the engine heats up quickly; 3. Fuel consumption increases significantly, and there may be backfire in the carburetor; 4. Difficulty in starting when the engine is hot, requiring much more throttle to start; 5. Carbon deposits on the valve and valve seat cone surface. For the knocking sound caused by valve leakage, it is due to continuous knocking between the tail end of the valve stem and its driving parts when the engine is idling. The sound increases with higher RPM, and there is little change in the sound when the engine temperature changes or the ignition is cut off. The sound of valve leakage is outside the valve chamber and is more noticeable under high load and low RPM. The usual solution is to grind the valves, check the valve springs, replace any damaged or weak springs, and readjust the valve clearance.