Why did my pressure washer’s motor suddenly stop?

Probable cause: It’s likely that your pressure washer is equipped with an ISS (Instant Start/Stop) switch. This switch is designed to keep the motor from running constantly, thus extending the life of your pressure washer. When the ISS is operating properly, the motor will come on each time the trigger is squeezed. If this does not happen, it is possible that the ISS and Unloader are sticking.

 

Tools that may be needed: channel-lock pliers

 

Steps to take: Try starting your pressure washer by carefully following each step below:

 

  1. Release the pressure on the pump by disconnecting the garden hose and high-pressure hose from the unit. The red light should be lit. If the red light is not lit, push in the “Test” and then the “Reset” buttons on the GFCI (Ground Fault Circuit Interrupter) plug.

 

  1. Reconnect the garden hose and high-pressure hose, squeeze the trigger and turn on the pressure washer.

 

  1. If The ISS and Unloader are sticking, this procedure should jolt them loose enough to be able to restart your pressure washer.

 

  1. If this procedure works, turn off the pressure washer and continue with the following steps in order to clean and lubricate the unit. If the unit still will not start, proceed directly to Step 7.

 

Cleaning and lubricating the pump:

 

  1. Reconnect the high-pressure hose and squeeze the trigger to relieve any pressure.

 

  1. Disconnect the garden hose from the pump.

 

  1. Using a funnel or short length of garden hose, pour 2 cups of vinegar into the inlet side of the pump. Squeeze the gun trigger and briefly turn on the unit to engage the pump only long enough for all the vinegar to circulate through the pump. Do not leave the pressure washer running. This is meant to clean the pump and free any internal components that are stuck.

 

  1. Unplug the unit. Let the vinegar set inside the pump 3-4 hours then flush it out with water.

 

  1. Again, using a funnel or short length of garden hose, pour 2 cups of vegetable oil into the inlet side of the pump. Repeat Step 3, using the oil in place of the vinegar. This will lubricate and protect the internal components.

 

  1. Unplug the unit. Let the oil set inside the pump 3-4 hours, then flush it out with water.

 

  1. If the unit still does not start, this indicates a more serious condition in the pump or the motor. Consider replacing the unit as there is no way to repair this problem.