1) Disassembly and assembly of fuel transfer pump
(1) Before disassembly, push the roller by hand for reciprocating motion, and check whether the roller (and tappet and ejector rod coupling) and piston movement are blocked E and the stroke is too small, and judge whether the piston spring works normally from the strength of the piston rebound ability;
(2) Pull out tappet and ejector rod; Disassembly, maintenance and assembly of plunger type A fuel injection pump
(3) Remove the hand pump components and oil outlet pipe joints, and take out the check valve springs and check valves at the oil inlet and outlet;
(4) Unscrew the plug of the oil transfer pump, and take out the piston spring and piston;
(5) Remove the hand oil pump components;
(6) Assemble the fuel transfer pump in the reverse order of disassembly, and pay attention to keep it clean during assembly; During the assembly of piston, ejector rod and roller body, the surface of parts shall be coated with appropriate amount of lubricating oil; The gasket used for sealing shall be installed with uniform end face.

2) Maintenance of oil transfer pump parts
After the disassembly of the oil transfer pump, check the wear of the inlet and outlet valves and valve seats: replace them if they are broken or severely worn; If it is slightly worn, it can be ground and repaired; If the piston and housing of the fuel transfer pump are loose or move unevenly due to wear, replace the pump with a new one.

3) Test of oil transfer pump
The performance test shall be carried out after the oil transfer pump is reassembled. The working performance index of the oil transfer pump is mainly the oil supply pressure and oil supply volume. The oil supply pressure is generally 49-196kPa. The working performance can be measured on a special test bench.
(1) Sealing test:
Tighten the handle of the hand oil pump and block the oil outlet, immerse the oil delivery pump in clean kerosene or diesel oil, pass 147-196kPa compressed air through the oil inlet, and check the air leakage between the pump body and the push rod. Collect bubbles with a measuring cylinder. If the volume collected in 1min is within 50ml and the bubble diameter is not more than 1mm, it means that the gap is normal and the seal is good, otherwise it should be repaired or replaced. The oil transfer pump can also be tested for tightness on a special test bench. When the oil supply pressure is 98 ka and the working speed is 50 r/min, there shall be no oil leakage within 1 min at the joint between the push rod and the pump body.
(2) Oil absorption capacity test:
Install the fuel transfer pump on the fuel injection pump, connect it to the fuel inlet of the fuel transfer pump with a rubber hose with a diameter of 8-lOmm and a length of 2m, and test the fuel absorption capacity of the fuel transfer pump from the fuel tank below 1m. When the rotational speed of the fuel injection pump is 200r/min, the fuel delivery pump shall suck out oil within 18s, which is qualified; If the fuel injection pump rotates for more than 36s and the fuel delivery pump has not supplied oil, it means that it needs to be repaired.
(3) Performance test of hand oil pump:
Drain the diesel oil in the oil inlet pipe, and then pull the handle of the hand pump back and forth at the speed of 2-3 times per minute, and record the time that the diesel oil is transferred from the fuel tank with the liquid level no less than lm below the oil inlet of the oil transfer pump to the oil outlet, which should not be more than 1min, otherwise it should be repaired. The test shall be carried out under the condition that the pipeline is well sealed. The hand oil pump operator: the oil discharged during operation shall be free of foam.
(4) Fuel supply pressure and fuel supply test
Install the oil delivery pump on the test bench. When the speed is 600r/nfin, the oil delivery pressure should not be less than 147kPa. When the speed is 750r/min, the oil delivery pressure should be 206kPa. When the oil delivery pump continuously supplies oil, the oil volume should not be less than 250ml/min.