有一台东方红-75型拖拉机在推土作业过程中,功率逐渐降低,冒黑烟,直至不能工作。开始驾驶员认为是燃油系的问题,便到修理厂校了油泵,调整了供油时间,但启动试车时,冒黑烟的现象仍然存在。于是,又更换了曲轴、缸套、活塞、活塞环。再启动试车,冒黑烟的故障排 There is a Dongfanghong -75 tractor in bulldozing operations, the power gradually reduced, black smoke until it can not work. At the beginning, the driver thought it was a problem with the fuel department. He repaired the pump at the factory and adjusted the fuel supply time. However, when starting the test run, the black smoke still existed. As a result, they replaced the crankshaft, cylinder liner, piston, piston ring. Then start the test run, black smoke fault row