Common causes of runaway slave unit are:

(1) The governor sensitivity bad, when a large load unload the gas can not be reduced, resulting in runaway.

(2) Total throttle lever and the governor lever loose connection point or a sudden loss during operation, causing the throttle out of control, resulting in runaway.

(3) between the governor and the fuel injection pump adjustment linkage has stuck phenomenon, when the load is reduced, the fuel injection amount minus down, causing coaster.

(4) fly weight governor shaft killed, causing loss of control and throttle coaster.

(5) The governor spring preload adjustable through the large, or the fuel pump when the zero adjustment oil appear positive, so that the amount of oil increases, causing coaster.

(6) diesel engine to the transmission mechanism governor is not normal, drive irregular, resulting in engine speed governor does not match its actual sensed speed, so that fuel adjustment mistakes coaster.

Of course, the coaster accident a machine reason caused such havoc, with overspeed protection device does not work also have a great relationship. The wheel control system over the past year three deputy machine fails often, can not be ruled out, put the three vice-machines are placed in the "manual" control bit, so that it cut the safety device, which several times coaster are in the sub-machine is in "manual" control occurs, the overspeed protection device is removed and can not stop in time to achieve protection, human parking attendant discovered after all, so the parking time delays, resulting in damage to further expand.