Improper adjustment of the engine control system will overload the engine, reduce the speed of operation and walking, and fail to exert the performance of the excavator. The excavator repair and adjustment of the engine control system must be carried out in accordance with regulations.
1. Engine control system assembly method The adjustment of the engine control system is shown in Figure 15-38
1) Adjust the assembly length of the rod 2 to about 250 mm.
2) In the above state, adjust the limit bolt so that the pedal is located at the upper end of the travel valve plunger 10. Note: Do not let the plunger be compressed.
3) After the rod 2 is assembled, hang the spring 7 between the rod 4 and the rod 8, and then adjust the rod 8 left and right to adjust the initial assembly length to 140 mm.
4) The length from the end of the draw bar 6 to the threaded part is about 150mm, insert the fork rod 9, and then fix the draw bar to the bracket. At this time, in order to prevent the tie bar from sinking or falling apart by more than 150 mm, the insertion depth of the fork rod 9 is adjusted or the threaded portion of the tie bar is adjusted left and right.
5) Inject grease into the grease nipple 5.
2. Engine speed adjustment method
(1) Checks and precautions before adjustment (Figure 15-39) 1) Tighten the bolt 5 to minimize the Lg of the head.
2) Set the start switch to the ON position and the engine control knob to the min position.
3) Assemble the pedal rib 9 and engine control motor rib 10 as follows.
①Assemble the pedal rib 9 according to the picture.
② The draw bar 9 is not allowed to sag. Before fixing to the bracket 2, pull the end by hand, but do not apply too much force.
③ With the adjusting rod 3 in contact with the limit block 11, fix the tie bar 9 to the bracket. In order to prevent the tie bar from sinking, after adjusting the left and right threads, use the fixing nuts to tighten on both sides at the same time.
(2) Speed adjustment in various operating modes 1) Engine control motor adjustment
① After the engine is started, the power mode is set to speed mode, and the automatic idle speed switch is set to the OFF position.
② Set the driving/operation selection switch to the operation position, and check whether the forward/reverse joystick is in the neutral position.
③Turn the engine control knob to the maximum position.
④ Adjust the variable resistance with a screwdriver so that the engine speed is within the range of (1750±50) r/min.
⑤Turn the engine control knob from the minimum position to the maximum position, and operate the walking/job selection switch to turn the maximum speed of the engine to (1900 t 50)r/min in this working mode.
Note: The speed difference when the engine speed changes from low to high and the speed difference from high to low may be different.
2) Adjust the pedal valve (Figure 15-39).
① Lower the left lever (the pilot cut-off switch is in the ON position).
② 4 in Figure 15-39 is the engine speed fine-adjusting plunger. According to the position of the travel/work selection switch, confirm whether it is the work mode or the walk mode. When it is working mode and walking mode, the stroke of the pedal valve is the largest, about 60mm.
Note: When in the operation mode, in order to retract the plunger, an appropriate external force is required.
③ After confirming, put the walking/operation selection switch to the operation position.
④ Slowly step on the pedal valve, adjust the rotation speed to (1750±50) r/min, adjust the length of the rocker shaft 6 so that the head contacts the plunger 4, and fix it with a nut.
⑤ Depress the pedal valve 2 to 3 times and check whether the engine speed is within the range of (1900±50) r/min.
(3) Automatic speed adjustment
1) Automatic idle speed adjustment
① After the engine is started, set the engine speed control knob to the maximum position.
② Put the walking/job selection switch in the walking position, the automatic idle speed switch in the ON position, and the power mode is I-speed mode.
③ Use a screwdriver to adjust the variable resistor so that the engine speed is within (1400±50) r/min.
2) II speed mode switching adjustment
① After the engine is started, set the engine speed control knob to the maximum position.
② Put the walking/job selection switch in the walking position, the automatic speed switch in the OFF position, and the power mode is I-speed mode. ③ Adjust the variable resistance with a screwdriver so that the engine speed is within the range of (1750±50) r/min.
3) I speed mode speed adjustment
① After the engine is started, set the engine speed control knob to the maximum position.
② Set the travel/operation selection switch to the walking position, the automatic idle speed switch to the OFF position, and the power mode is I speed mode.
③ Use a screwdriver to adjust the variable resistor so that the engine speed is within (1600±50) t/min.
