What are the reasons for black smoke from the Dewei D30 engine?

[LaMaya]

Dewei D30 engine emits black smoke for the following reasons: Oil in the exhaust pipe: It is necessary to check whether there is oil in the exhaust pipe. If the valve oil seal leaks, it will allow oil to leak into the exhaust manifold, and under high temperatures, this can also produce blue smoke. Excessive gap between piston and cylinder: Apart from oil in the exhaust pipe, most cases of blue smoke are due to an excessive gap between the piston and cylinder. If the piston rings cannot scrape off the oil cleanly, blue smoke will be emitted. Piston rings seized: Seized piston rings can also produce blue smoke because the piston rings play an expansion role inside. After an engine overhaul, it must be run-in according to specifications, and avoid slamming the accelerator.