What are the causes of poor valve sealing?

[StPatrick]

The causes of poor valve sealing are: 1. Insufficient valve clearance; 2. Excessive carbon buildup on the valve contact surface; 3. Deformation of the valve seat or valve head; 4. Valve spring failure or rocker arm deformation. The throttle valve is a controllable valve that regulates air intake into the engine. Its function is to control the air entering the engine, which mixes with gasoline in the intake manifold to form a combustible mixture for combustion and power generation. The steps for cleaning the throttle valve are: 1. Open the engine hood and locate the throttle valve; 2. Use a flat-head screwdriver to remove the air filter and intake pipe, then unplug the electrical socket on the throttle valve; 3. After removing the screws, take off the throttle valve and use a dry cloth to block the engine intake to prevent dirt from entering; 4. Spray the throttle valve with cleaner and clean it thoroughly.