The Diagnosis Indicates That The Excavator Operates Normally At Low Speed But Has No High Speed, Resulting in Insufficient Smoke Exhaust

The engine performs well at low speeds, but when accelerating, the speed never increases and the driving is weak. This is caused by insufficient circulating fuel supply.
Improper adjustment of the fuel injection pump led to a reduction in fuel supply.
② The spring of the governor has its elasticity reduced due to fatigue. When the accelerator is pressed to the bottom, the fuel level adjustment lever cannot move forward to the end, resulting in a reduction in fuel supply from the fuel injection pump and the engine being unable to reach the rated speed
③ The plunger and sleeve of the fuel injection pump, as well as the needle valve and needle body of the fuel injector, are severely worn, which increases the leakage of diesel during fuel pumping and relatively reduces the fuel supply.
④ Improper adjustment of the throttle control lever or excessive release of the throttle pedal prevent the pedal from reaching the designated position, resulting in insufficient fuel supply at full load.
⑤ There is air in the oil circuit.