In addition to ordinary tools, special tools must be used for the disassembly and assembly of the fuel injection pump and governor of Cummins generators, and the work site, workbench, tools and parts must be kept clean and tidy.

Decomposition of fuel injection pump parts: first remove the lead seal of the fastening splint, and remove the oil outlet valve seat and the oil outlet valve spring in order. When disassembling the delivery valve assembly, because the delivery valve nylon gasket is deformed and clamped on the pump body after use, special tools must be used to remove it (Figure 5-8). Then, use the screwdriver to pry up the plunger spring to take out the spring lower seat. Loosen the plunger sleeve positioning screw and use a thin iron rod to push the plunger upwards, and then the plunger assembly can be pulled out together with the blocking sleeve from above. The plunger assembly and the delivery valve assembly must not be touched or disassembled and exchanged. They must be placed in clean diesel oil in pairs.