实例一 故障现象:一辆雅马哈50踏板车,车主反映因拉缸而更换了活塞、活塞环,此后出现了启动困难,排气管冒黑烟,无怠速,载人不能行驶的故障。 故障分析与排除:首先试启动发动机,踏了十几下终于着了车,发动机声音沉闷,油门要加到中间位置才能不熄火。故障现象确如车主所述。拆去空气滤清器,再次试启动,只要几脚即可着车,且能调出怠速,排气管冒黑烟也有所改善,载人也能行驶,只是不如骑自行 Example A failure phenomenon: a Yamaha 50 scooter, the owner of the cylinder due to replace the piston and piston, piston ring, then there is a start-up difficulties, the exhaust pipe black smoke, no idle, the man can not drive the fault. Failure Analysis and Troubleshooting: First try to start the engine, stepped on a dozen finally got into the car, the engine sound boring, the throttle must be added to the middle position to not turn off. Fault phenomenon as described by the owner. Remove the air filter, try again to start, as long as a few feet to the car, and can be transferred out of idle speed, exhaust pipe black smoke has also been improved, people can drive, but better to ride their own