What are the reasons for black smoke from Dongfeng Tianlong?

[LondonLynn]

Reasons for black smoke from Dongfeng Tianlong's exhaust pipe: Symptoms of overly rich air-fuel mixture. Below are the relevant explanations: 1. Incorrect ignition timing: This can also cause incomplete combustion of the air-fuel mixture. Or if a few cylinders in the engine are not working, a small amount of black smoke may be emitted. 2. Overly rich air-fuel mixture: This means the air-fuel mixture in the cylinder has an excessively low air coefficient, leading to incomplete combustion. Some fuel decomposes into free carbon under high temperatures and is emitted from the exhaust pipe, forming black smoke. 3. Additional information: If the engine's exhaust pipe emits a large amount of black smoke accompanied by popping sounds, it can be determined that the air-fuel mixture is too rich. It is necessary to promptly check whether the choke valve is fully open and, if needed, perform high-speed maintenance.