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How do I replace an Unloader Valve in a Gas Pressure Washer?

The check valves allow water to flow from the pump inlet to the outlet in one direction. The pressure washer won't spray if check valves are worn out. If the pump check valves are not working, they should be replaced.

The chemical injection system mixes the detergent with the spray after sucking it from the soap container. If the detergent doesn't flow through the system, it's time to check the injection components. There are chemical injection components that should be replaced.

When the engine is running, the water pressure is created by the pump. The pump assembly should be replaced if the water pressure isn't developing.

When the pump runs but the spray wand is not used, the unloader valve reduces water pressure within the pressure washer pump. The thermal relief valve discharges hot water onto the ground if it sticks in the closed position because the unloader valve can't open. The unloader valve could be stuck open if the pressure washer does not develop adequate outlet pressure. If the unloader valve sticks in either position, replace it.

Follow these steps to fix your issue:

  1. Disconnect the spark plug wire

    The spark plug has wires connecting it to the spark plug.

  2. Disconnect the hoses attached to the pump

    The inlet water hose needs to be removed from the pump. The nozzle hose has to be removed from the pump. If there is fluid in the chemical injection tube, it's time to tighten it. The chemical injection tube can be removed from the inlet valve.

  3. Remove the pump

    The pressure washer has a pump on top of it. The Allen-head mounting bolts that secure the pump to the engine should not be loosened. Remove the Allen-head mounting bolts from the pump when using the pressure washer upright. If you want to remove the pump from the engine, you should pull the pump off of the engine's crankshaft.

  4. Prepare the new pump for installation

    The old pump has a thermal relief valve. To seal the thermal relief valve connection, use pipe thread sealing tape.

  5. Install the new pump

    Align the notch with the key on the engine crankshaft by rotating the pump drive connection. The pump should be on the engine crankshaft. The mounting holes need to be aligned with the pump. Attach the Allen-head mounting bolts securely.

  6. Reconnect the hoses on the pump

    The chemical injection inlet valve has a chemical injection tube on it. The chemical injection hose should be removed if used. The inlet water hose connection on the pump is connected to the nozzle hose.

  7. Reconnect the spark plug

    Attach the spark plug wire back to it's place.

  8. Test the new pump

    The pressure washer needs to be started and tested.

  9. Disconnect the spark plug

    The pressure washer engine has a spark plug.

  10. Remove the unloader valve

    To remove the unloader valve, use an open-end wrench.

  11. Install the new unloader valve

    The O-ring needs to be put on the unloader valve. The O-ring on the unloader valve should be Lubricated. Put the new unloader valve into the pump. You can tighten the unloader valve if you have a Torque wrench.

  12. Reconnect the spark plug

    Remove the spark plug wire from the engine.

  13. Check pressure washer operation

    Check for water leaks at the unloader valve when you start the pressure washer. Make sure the unloader valve works correctly.

Time required:

15 minutes.

You would need the following tools:

allen head bit set and ratchet, silicone lubricant, torque wrench (optional), work gloves, wrench set.

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