During the operation of the tractor, the engine speed is unstable, which needs to be eliminated in time, otherwise it may cause serious consequences. For specific exclusion methods, please refer to the following three points:
1. If the tractor runs smoothly under heavy load, but it runs smoothly when it is empty or going downhill, check whether the fuel system is blocked to prevent oil from flowing in.
2. Remove the cover plate of the observation hole on the gear chamber cover, start the engine, press and hold the speed regulating lever with a screwdriver to fix it at a certain position. If it runs smoothly at this time, it indicates that the fault may be in the governor part. The following inspection should be carried out: first, check whether there is too loose place at each connection of the external speed regulating mechanism of the engine, otherwise, remove the loose obstacle. If the operation is still unstable after troubleshooting, remove the gear chamber cover and check the internal structure of the governor. The internal structure of the Governor shall mainly check whether the gear shaft of the governor and the body are loose, and whether the two forks of the short arm of the governor lever are uneven. If the two forks are seriously worn, a paper gasket with a thickness of about 1mm can be added between the speed regulating sliding disc and the one-way thrust bearing. Note that the paper pad should not be too thick, otherwise, the maximum speed of the engine will be reduced, thus reducing the power. If the unstable speed cannot be eliminated after the above treatment, it is also necessary to check whether the speed regulating lever is blocked, whether the piston adjusting arm of the fuel injection pump is too loose in the fork groove of the speed regulating lever, and whether the rotation of the plunger in the plunger sleeve is blocked and inflexible.
3. Press and hold the speed regulating lever with a screwdriver. If the operation is not stable, it means that the fault is not in the governor. Check the fuel system. First of all, loosen the oil pipe joint nut on the fuel injection pump. If bubbles are found, it is sure that air enters the oil path. Check whether the oil pipe is broken and the pipe joint nut is loose. Pay special attention to whether the gasket of the oil outlet valve of the fuel injection pump is cracked or not, and whether the positioning screw of the oil pump plunger is loose. If the engine speed is still unstable after the above inspection and repair, remove the fuel injector from the cylinder head and replace it with a new one for test. If the fault is eliminated, the fault is on the injector; The fuel injector can also be removed and reinstalled on the high-pressure oil pipe, and the engine can be cranked to observe the fuel injection of the fuel injector. In case of poor atomization, oil dripping or stuck needle valve, grind or replace it.
