1. Black Smoke When the engine turns, black smoke is emitted from the oil filler port and is accompanied by a knock. Explain that the cylinder liner and piston are worn, the fit is too large, or the piston ring leaks. 2. If the engine oil is used to spray oil from the oil filling port when the engine is working, it means that the cylinder sleeve and the piston have been seriously worn, and the piston ring may be broken or stuck, or the cylinder may have been pulled. The combustion chamber's high-temperature and high-pressure gas generates a serious “lower rowâ€. Gas phenomenon. At this time, the engine power has dropped significantly, and the fuel consumption has increased dramatically. It should be stopped and overhauled immediately. 3. After starting the white smoke engine, white misty smoke emerges rhythmically from the oil port, which is a precursor to burning tiles. Due to the high temperature caused by dry friction before burning tiles, the temperature of the local oil increases sharply, and some of the oil is evaporated into white mist-like particles to exit the crankcase. At this time, the machine should be shut down for inspection. It is impractical to avoid accidental shaft suspension. 4. Hearing abnormal noise If you hear a short “dang and when†sound at the oil filling port, the sound of the engine is more pronounced when the engine suddenly accelerates at idle speed; the higher the speed is, the louder the sound is; the single cylinder is off fire (broken off) When the sound is weakened or disappears, it can be judged to be an abnormal sound from the connecting rod bearing. Should consider whether the connecting rod bearing clearance is too big, the connecting rod bolt is loose, uses after eliminating the breakdown.