Pressure Washer Stalls Under Load (Resolved!)

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​Does your pressure washer stall under load? Don’t worry, we know exactly what to do when a pressure washer stalls under load-- and we’ll teach you how.

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​A stalling engine is a pretty common problem to have if you own a pressure washer. However, it is one that you may need to address right away because it means that there is a problem with one of the parts. If that is the case, you need to make sure that these parts are checked and fixed or replaced as needed.

​If you haven’t really dealt with a pressure washer before, then you’ll need some instructions on what to do when a pressure washer stalls under load.

​In this guide, we’ll give you the top reasons as to why a pressure washer dies under load and what to do about it.

​Top Reasons Why Pressure Washer Stalls Under Load And How To Fix Them

  • ​Problematic Carburetor

​The first part that you may want to take a look at is the carburetor. There are two possible problems that your carburetor may have in this situation.

​It’s either your carburetor is loose or clogged. If it’s loose, then it’s really as simple as tightening it in place and fixing its position. However, clogged carburetors will need to be cleaned.

​The main reason as to why clogs happen is because of old gas that gets stuck there for a month or more. In this case, you just need to drain the gas tank, take out the carburetor, and clean it. If those two fixes still don’t work, you’ll need to replace the carburetor.

  • ​Faulty Unloader Valve

​Another reason why a petrol pressure washer dies under load is because of a faulty unloader valve. You see, a faulty unloader valve keeps the pressure inside the pump.

​When the pump’s pressure gets too great, it becomes greater than even the engine’s power. When this happens, the engine will start moving and stall.

​If you think that the problem lies with the unloader valve, simply check the pump system’s topside and look for the unloader valve. You need to check if the unloader valve diverts the water flow properly. If not, then you may need to replace your unloader valve.

  • ​Dirty Air Filter

​If your air filter is dirty, your pressure washer won’t be able to regulate the air pressure inside properly. This also stalls your engine. All you have to do is to simply take out your air filter and clean it out.

​Usually, debris will block the air filter. You’ll just need to use a dry or damp cloth to clean out the dirt.

  • ​Low Oil Levels

​The simplest thing to do when your engine is stalling is to check the oil levels. All you have to do is check the levels. If they’re low, you simply need to refill the oil and you should be able to get your machine started up again.

  • ​Disconnected Spark Plug

​Another reason as to why your engine will stall is because of a disconnected spark plug. If the spark plug is loose, you just need to connect it back in tightly.

  • ​Smoking Engine

​When your engine stalls, there is a huge possibility that the engine will smoke. If that happens, you need to check either of two things-- the choke position and the air filter.

​For the air filter, you need to check if it’s clean or damaged. If it’s dirty, you can follow the tip we gave above. If it’s damaged, you may need to change it. The other thing you need to check is the choke. If it is turned on, you need to turn off the position.


​As you can see, a pressure washer has so many aspects that you need to check in order to know if the engine has a problem. If the pressure washer stalls under load, chances are that the parts near the engine contribute to the main issue. So, the next time that your engine doesn’t want to turn on or stalls, just follow the steps provided in our guide.

​As long as you troubleshoot the parts that we’ve mentioned above properly and follow the fixes that we’ve given you, you should have absolutely no problem with your machine.

​We hope you were able to learn something from our guide and have a really good day!

Mattie Keyes

Hi there! This is Mattie. When I am not making DIY projects for my house, I spend most of my time researching and writing reviews of different products that you can buy online. I am an office worker turn full-time blogger, and I hope to help other homeowners like me on how to improve and reinvent your home using the best ideas and equipment.