How to Install a Plunger Pump

Plunger pumps are basically designed for applications that include pressure washing. The pumps can be designed with various types of systems, such as belt drive, electric motor driven, and gasoline, direct drive systems. These motors have to be installed in a specific manner to ensure smooth operation. All the components and tools are provided by the manufacturer. The installation of a direct drive plunger will be discussed here.


  1. 1
    Install the shaft key: The shaft key consists of a depression that allows the engine keyway to go through. Hold the shaft key with both hands and align the shaft key with the keyway. Gently slip the shaft onto the keyway and push forward till it flat against the engine
  2. 2
    Set up the pump: The pump has two keyways that allow for installation with the engine. Align the keyways with the keys of the engine and slide the inside. Once the pump is secured, push it forward until the pump is completely connected with the engine.
  3. 3
    Screw in the pump bolts: Take the pump bolts provided by the manufacturer. Place them in their respective pre-designed holes. Screw them in until they are slightly tight. Complete their installation by using a wrench.
  4. 4
    Remove the oil cap: Generally, the bolts are covered with shipping oil caps, which are in color. Remove these and ensure that bolts are secured.
  5. 5
    Install the vent cap: The crankcase also comprises bolts. To keep them protected, cover the bolts with the crankcase vent cap that is provided by the manufacturer.
  6. 6
    Apply anti-seize: The anti-seize lubricant is used to protect the engine shaft from corrosion or galling of any kind. Spray a light coating of the lubricant and allow it to dry before moving onto the next step.
  7. 7
    Attach the miscellaneous components: Begin installing all the other accessories and miscellaneous components that have been provided to you. Start by installing the unloader valve. Then move onto water inlet and discharge fittings.
  8. 8
    Connect the water supply accessories: After the above components have been installed, attach the water supply hose and water spray gun. The spray gun is a high discharge type. Ensure that it is properly secure before you use it.
  9. 9
    Check the safety relief valve: Every plunger will have a safety relief valve that is installed on the discharge side. Check whether the valve is closed and is allowing the correct amount of pressure.
  10. 10
    Start the spray gun and water supply: First, open the spray gun to make sure that no air is left in the system. Once this has been done, then turn on the water supply.
  11. 11
    Start the engine: Turn on the engine and start it. Adjust the engine speed as well as the unloader valve to your requirement.


  • Always wear the requisite safety goggles, gloves, and clothing (if any) when installing and operating the pump.
  • Use only clean filtered water for the pump.


  • Do not operate the pump in a confined or explosive environment. Always make sure that the room is ventilated.
  • Do not exceed the pump’s specifications in terms of speed and pressure.

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Categories: Home and Garden