The coaster of a diesel engine refers to a failure in which the speed of the diesel engine is lost and the speed is getting higher and higher. Speeding can cause serious accidents such as boring and broken shafts in diesel engines. Generally, the diesel engine will only fail when the load suddenly disappears or decreases during the start-up or work, but under the load, no fault occurs. The reasons for the occurrence of the coaster are as follows: 1. Excessive lubrication in the governor casing, swift throwing of the governor speed, affecting the governor effect; slipping of the governor friction clutch; governor high speed limit screw and safety gear loosening; Escaped quickly or stuck; speed control spring breaking, thrust bearing or governor bearing damage, so governor failure, resulting in speed. 2. The governor drive slip sleeve of the single fuel injection pump of the single-cylinder diesel engine is stuck, causing speed regulation failure and the occurrence of speed failure. 3, injection pump plunger due to the installation of skew or oil stuck, there can be rotated, so that speed boat loss of boats, especially multi-cylinder pumps, there will be reduced load, fuel supply can not be changed caused by speed. 4, fuel injection pump oil adjustment teeth stuck in the maximum fuel supply position or rack and governor lever off, lost control, resulting in speed. 5, some fuel injection pump plunger on the inlet and outlet hole in the same plane position, if the plunger set screw is too long blocking the oil return hole, causing poor return oil, resulting in soaring oil supply will also cause Speed. 6. Inertial oil bath air filter oil is too much oil, was sucked into the cylinder combustion, equivalent to increase the amount of oil, but also to speed up, resulting in speed. When a diesel engine takes off, it will cause serious consequences if it does not immediately stop and extinguish. Therefore, when a speed occurs, you must find a way to immediately stop and turn off the diesel engine. Emergency measures include: 1. Put the accelerator handle to the position where fuel is not to be provided, and then turn on decompression. The device allows the cylinder to extinguish without compression. 2. Loosen the high pressure tubing connector nut with a wrench so that the diesel engine does not supply oil, and the diesel engine can also be turned off. 3, block the intake pipe, diesel engine does not suck into the air, it will turn off. 4. High-grade heavy load is available in the driving state, that is, the brake will reduce the engine speed and extinguish the flame again. After taking emergency measures to turn off the diesel engine, it can eliminate the fault of the vehicle according to the aforementioned principle.