What Causes Blackening of the Exhaust Pipe?

[DelMiles]

The reason for the blackening of the exhaust pipe is that the oil vapor does not burn completely, and some of it is carbonized when passing through the three-way catalytic converter. The accumulated carbon over time leads to the blackening of the exhaust pipe. Precautions for exhaust pipe maintenance include: 1. Close the choke when starting the engine cold in winter and open it promptly after the engine warms up; 2. Avoid installing windshields or decorative items in front of the engine and muffler as they may affect heat dissipation; 3. Avoid prolonged driving at high load in low gear, which can damage the engine and muffler; 4. Avoid revving the engine at high speeds while stationary for extended periods; 5. Clean the muffler surface promptly when it is covered with a large amount of mud or other dirt to prevent affecting heat dissipation; 6. Ensure the muffler gasket is properly installed and tightly secured during installation to prevent air leaks.