Pressure Washer Shuts off when Trigger Released (SOLVED)

If your pressure washer shuts off when the trigger is released, it has a problem with the unloader valve. There are a few issues with your unloading valve that causing stalling the engine pump. Troubleshooting of this problem is pretty simple and you can do it yourself easily.

We are going to discuss the troubleshooting procedure step by step. Keep reading the article to learn those steps.

Required Tools and Items:

  • A screwdriver
  • A wrench
  • Alcohol/kerosene
  • Grease

Step One

Take a wrench and a screwdriver to unplug the unloader valve from its bay. First of all, unplug the valve retaining pin that locks the unloader valve with its bay. Typically, most of the pressure washer manufacturers keep the unloader valve visible. Even if you have the most powerful pressure washer like the best 3000 psi pressure washers, no need to worry to locate the retaining pin.  The retaining pin is something like a U-shape pin (a common shape for most of the pressure washers). Insert your screwdriver inside the retaining pin and pull it up to unscrew the pin.

pressure washer shuts off when trigger released

Step Two

Now, use the screwdriver to pull the unloader valve from its bay. A gentle pull is enough to do that. One of the major parts of the unloader valve is its piston that controls the pressure retention. This piston moves forward and backward when you run the pressure washer. If the piston can’t move freely, your pressure washer shuts off. So, inspect the piston whether it is moving freely or has some issues to move.

Step Three

If the piston is moving freely, skip this step and go to the next step. If your piston is not moving freely, you have to work on it. Unplug your piston from the unloader valve. Use your wrench to unscrew the nut that fastens the piston with the valve. Unplug the spring and piston from the unloader valve. Now, clean the spring and piston with alcohol or kerosene. After that, grease the spring and piston with good silicone grease. Now, set them back to their respective places. This will allow the spring and the piston to work smoothly.

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Step Four

The unloader valve has a setting to produce pressure depending on your job. Check the valve setting to ensure it has a perfect setting. Maybe, your unloader valve has a too high setting that’s stacking the engine when the trigger is released. Your unloader valve must open up to cycle water back to the inlet side. When the valve fails to open up, it builds up high pressure that stalls the engine. So, adjust your unloader valve setting if required.

Step Five

Sometimes, the pressure washer shuts off due to the problem with the O-rings. Your unloader valve has  O-rings that are generally known as washer or seal. If the O-rings are torn out, deteriorated, or in a poor state that is not enough to seal the oil pump, it may fail your unloader valve to work properly. Replace the O-rings with exact size ones. This will ensure proper sealing of the oil pump.

Last update on 2024-03-13 / Affiliate links / Images from Amazon Product Advertising API

Step Six

Inspect the pressure gun for its serviceability. If it is not in working condition, only adjusting the unloader valve may not bring the perfect result you are looking for. Adjust your pressure unloader valve and consider buying a new gun as well.

Last update on 2024-03-13 / Affiliate links / Images from Amazon Product Advertising API

Step Seven

If you have done with the abovementioned steps but the problem remains as it were, try the followings:

  • Inspect and clean the air filter
  • Clean the spark plug with alcohol
  • Inspect the water inlet
  • Inspect the wand screens

If everything is working fine but the problem remains, you can go for a local expert or consider buying a new unloader valve.

Last update on 2024-03-13 / Affiliate links / Images from Amazon Product Advertising API


Using a machine with trouble kills your mental serenity and creates instability. Take care of your pressure washer so that it can care for you in return. We hope that this article on “pressure washer shuts off when trigger released” was a bit helpful for you.


31 thoughts on “Pressure Washer Shuts off when Trigger Released (SOLVED)”

  1. Thanks to this article I saved a bunch of money by not going to a professional technician and was able to complete the repair midway into a job and continue on to finish the job same day with no earnings lost. Thank You so much for this detailed information. It has helped me out tremendously. Aaron P.- WA, USA

  2. What if the pressure washer idles fine, but then shuts off immideately after you pull the trigger? I have a Ryobi 3100 model and I have cleaned the carburator, I have checked the unloading valve and it looks good, I have fresh fuel, changed the oil, cleaned the spark plug, but it keeps shutting off once I pull the trigger.
    Any thoughts

    1. Hi Manos,
      Seems that it is time to replace your carb kit. Have you replaced your carb kit before? How long have you been using this Ryobi? Sometimes, an aged carb kit may look fine but not capable of supplying fuel to the piston. What about your O-rings? Is that in working condition? Either you replace your old carb kit and O-rings or consult with a local expert.

      1. I have simpson 3000psi when I turn on it’s come one with press of gun but then it’s go out. If I do not press the gun then it have lots of pressure build to it as soon as I press gun it’s release the pressure. Can you let me know what can I do to fix it.

  3. Thank you for taking the time to reply.
    It’s about 8 years old but it has been barely used. It’s been used max once or twice every summer season.
    Which O-rings are you referring to? The unloading valve ones? I’ve checked those and at least visually they look OK. I was wondering if it’s possible that there’s an issue with the pump which I don’t know if it’s serviceable at all.
    Thank you again!

    1. Yeah, we were referring the ones on unloader valve. They might have been ok as you visually found so. Have you found any abnormal pressure decreasing? If your pressure washer is not capable of generating its rated/working pressure, there might have been issues with your pressure pump. But, a bad/faulty pump does not shut down the engine. You better consult with a local expart. We appreciate your patience for our reply.

  4. Hey, pressure washer will start fine when I’m holding down the trigger. It will run all day when I’m pulling the trigger, but when I let it go, it’s just a matter of seconds before it dies out. Sounds like the unloader valve? Thanks

  5. Have an odd one for you…pressure washer runs fine but gun only trickle sprays when squeezed…but if I choke the engine then return to full power while holding gun on them it goes to full strength spray until I let off the trigger.

    Found this out while my wife was helping me try to troubleshoot.

    Any ideas? I tried to keep this brief. Thank you guys.

    1. Hi Mike,
      Clean your carb kit with alcohol or kerosene. Your problem is the result of carburetor malfunctioning. Do not forget to check the air & fuel filter for clogging. Hope it helps.

  6. Hola, tengo una Ryoby 1600 psi electrica modelo 141612,el problema es que se prende y se apaga sola aunque no jale el gatillo, que problema tendrá??

  7. Pressure washer works fine until I release the handle, motor stops ok but just hums until it trips the circuit breaker. whats up with that?

    1. Hi Rick,
      How old is your power washer? Is it an electric washer or gas-driven?
      If it is an electric power washer, check the serviceability of the motor coil & lubricate the path in which the motor orbits.
      If it is a gas-operated power washer, check the pump oil and the said path. If found bad, change the engine oil and lubricate the path. Hopefully, your problem will be solved. Thanks…

  8. I have a Craftsman 2450 PSI washer. It will run with no hoses attached. It will not start if water is supplied unless I squeeze the trigger on low. It will run fine as long as I squeeze the wand trigger, and only on low. If I let go of the trigger or switch to high, the engine stalls out. Any suggestions? The piston on the unloaded is operating, and the little opening on it looks clear. Is there a passage where the unloader is inserted that may be clogged? Thanks.
    If I have the engine running and connect a water supply and no hose on the outlet, the water does spray out the output at a high velocity. I believe the wand and nozzle are clear, as water will flow on low and high settings with the engine off.

    1. Update. If I adjust the pressure on the unloader valve low enough it will stay running with the trigger released, and with the nozzle set on high.

  9. I have a Generac power washer That gets hot and shuts off after 10 seconds. Can you tell me what to look for that would Create this problem

    1. Hi John,
      We are not clear about your query. Does your power washer gets hot and turns off within 10 seconds of operation? Or does it turns off after 10 seconds of getting hot ( it maybe running for a while)? Anyway, it would have been better for us to reply had we understood the issue.
      Probable cause & solution: There is a thermal protector valve for the pressure washer pump that relieves heat. Once the valve becomes faulty or unable to do its part, the power washer gets hot and turns off. In this case you need to change this thermal relief valve.
      Another possible cause is faulty unloader valve that may fail to regulate pressure. In that case you need to adjust the unloader valve. If the valve still fails to regulate the pressure, replace it.
      We recommended you to read your owner manual to seek whether this failure is included in the troubleshooting section. Thanks…

  10. Have a Honda gx390 pressure starts fine an builds up pressure.. but when I press the trigger on the gun it losses pressure.

  11. Hi. Great info you share. But my issue is a bit different. Briggs 4.5 motor with a new 2700psi pump. ((Old unloader broke, cheaper to buy new pump)) Motor starts ok, pull trigger I have good pressure for a few seconds then no pressure, release trigger for few seconds, pull trigger and pressure is back. This happens over and over and over. This new pumps water inlet had a plastic cone screen, I pulled it out now pressure is constant. But now when I pull trigger the motor rpm drops to very low rpm and almost dies but stays running. Release trigger and motor rpm picks right back up. Does new pump, that came with unloader, need adjusting???

    1. Hi Jack,
      You need to adjust the new pump and unloader valve depending on the level of your jobs. Moreover, check the wand to ensure that it doesn’t create the hazard that you are facing.

  12. Just bought a ryobi rpw130xrb pressure washer. Works great but when using if i releasevthe trigger on lancecthere is a whirring noise for couple seconds sounding like a pump drive or something slowing down or stopping. Iscthis noise normal and is it just the motor stopping itself ? Thanks Simon

  13. Hi , Thanks for the very helpful article
    I have an unloader valve that has the piston and spring that sit inside a brass housing. The spring just falls out when I unscrew the top half of the housing.

    Is the piston suppose to be able to come right out of the brass housing? Mine is in very tight

    How much should the piston move? Mine only moves a few mm back and forth with the top unscrewed. As soon as I screw the top back on, I cannot move it at all.
    Thanks for your help

    1. Hello Terry,
      Sorry for the late response. Are you still struggling to fix the piston? It seems that the piston is not properly placed in its housing. Let us know your present situation. Thanks…

      1. Thanks for the response TH
        Yes I am still having the issue of the motor shutting down when I release the trigger. It’s a Briggs& Stratton 550 series model 020439-00 with an AR42118 type unloader. I am not sure how the piston comes out or how much it is supposed to move. When fully assembled, I cannot push the piston in or out(spring inside is quite heavy) When top part of housing is unscrewed, it moves back and forth a few mm. Not sure if it’s the unloader or pump issue.

  14. ok my presure washer seems to work great turns on and off. but when I run more restrictive tips it take a few second for high pressure to start giving me full power. and when I put on a foaming end onto the gun its even worse it accually cycles between high pressure and low pressure about 5 seconds each. is there any adjustments I can make to give me high pressure faster and more constant, i assume it as something with the diffrential pressure valve or something.

    1. It seems that you need to adjust the unloader valve of your pressure washer. That might help the washer to produce the optimum pressure flow irrespective of tips or cannons. If you don’t know how to adjust the unloader valve, search on this site to get the definitive guide on unloader adjustment.

  15. When the handle trigger is released the engine stalls. In 95% of the case this is the unloader valve, but I experienced a faulty trigger at the handle!! I borrowed the neighbors machine and used my handle / trigger and the same problem happened with the borrowed pressure washer.

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