Pressure Washer Engine Stops Running While In Use


You have just woken up on a fine weekend morning, and cleaning your car is the first thing on your to-do list. However, your very own pressure washer you have been using for a long time shuts down just after starting. If you haven’t done DIY work before and don’t exactly know where to troubleshoot from, then there is no need to panic since we have got you covered in this article that provides you with all the necessary steps details will make your washer up and running again.

Pressure washer engine stops running, what to do:

  1. Cleaning the fuel cap to eliminate vacuum formed in the tank
  2. Replacing the fuel filter that gets clogged due to debris
  3. The clogged carburetor in which restriction prevents the air-fuel mixture to be drawn in an appropriate amount

Some additional causes include:

  1. A clogged air filter that does not provide a clean air-fuel mixture to the engine
  2. Blackened fire arrestor screen that prevents spark formation
Pressure Washer Engine Stops Running While In Use 1
(CC BY-SA 2.0) by K.Logan.Sullivan

If a pressure washer does not start, the most probable cause is the absence of combustion in the engine, resulting in a successful power stroke. This problem may be linked to several reasons. We shall describe each of these causes individually.

If you aren’t sure how you would locate, change, or clean these components or what procedure you should be following, don’t worry. We have listed all the necessary steps with a detailed explanation of the steps that will resolve your engine shutoff problem.

Steps To Troubleshoot Engine Shutdown:

Engine shutoff right after its start or, in other words, engine stall, is more related to the presence of dust or debris in filters and plugs rather than the failure of an engine component. Here, we shall list down the five most frequent causes along with what you need to do to ensure that the machine does not stall.

1. Cleaning the Fuel cap:

The fuel cap in your engine is designed with vent holes that prevent the formation of a vacuum in the fuel tank so that the carburetor draws the appropriate amount of gasoline to supply it to the engine. Over time, the impurities in the fuel and dirt particles in the environment clog the vent holes hence forming a vacuum in the tank. A vacuum lock within the tank prevents the carburetor from drawing fuel, eventually causing the engine to shut down and make it look as if the gasoline ran out.

– Solution:

The remedy to the problem is a simple one.

  • Eliminating the vacuum formed: Open the cap for a few seconds so that air enters into the fuel tank. The carburetor will now draw the gasoline to supply it to the engine, and it won’t stop until the vacuum lock is created again.
  • Cleaning the fuel cap: As a permanent solution, you can use a thin metallic wire to clean the cap’s clogged holes. If the holes remain clogged, then you probably would need to replace the cap.

2. Replacing the fuel filter:

In your machine, a fuel filter is situated just before the entry of fuel into the carburetor. Dust particles or debris may be present in the fuel that needs to be filtered off. The fuel filter serves this function. Over time, several dust particles and fuel impurities get sucked into the filter, making its pores clogged and not providing the carburetor with gasoline supply. As a result, your engine will shut down just after starting making you wonder went wrong.

– Solution:

  • Diagnose fuel quality: To solve this problem, you should first diagnose fuel quality in your tank. A heavier and stickier fuel will show that its quality has deteriorated over time and will mean that the filter might be clogged.
  • Replace the fuel filter: As a solution, you should first drain off all the fuel in your tank. Then you should replace the filter and add fresh gasoline into the tank.

3. Clogged Carburetor:

More often than in other cases, a clogged carburetor is a leading cause of engine stall problems. A carburetor is a component where the fuel mixes with air in a fixed proportion so that effective combustion can take place. When an engine shuts down while running, it probably means that no combustion occurs in the engine. In most cases, a clogged carburetor is an issue that you need to look out for.

– Solution: Servicing the carburetor:

To clean the carburetor, you should follow the steps below:

Step 1: Unscrew the front cover

To view the carburetor in your pressure washer, you should first unscrew the front cover and air filter door.

Step 2: Remove the carburetor

Next up, you carefully need to disconnect the fuel lines leading to your carburetor. Exercise caution while removing the clamps so that no fuel leakage occurs. Also, there might be two screws connecting the carburetor to a linkage. They also need to come off.

Step 3: Disassemble

Now that your carburetor is removed, carefully disassemble its screws and jets. We recommend that you make a video during disassembly or take some photos to keep track of the parts. This will help you in assembling them back.

Step 4: Check and clean

Afterward, you should check the jets and screws for debris build-up. You can use a carburetor cleaner liquid to unclog the jets. If available, you can also use compressed air for cleaning the holes.

Step 5: Assemble

Now you should carefully assemble the individual parts and put the whole assembly back in its original place.

Additional Steps:

4. Cleaning the air filter:

Just like a fuel filter, an air filter is a spongy material situated in your machine with the purpose to filter off foreign dust particles in the air. If engine stalling occurs, one reason might be that your engine isn’t receiving an appropriate proportion of air, and that might be when the air filter is clogged with dust particles and needs servicing.

– Solution: Servicing the air filter:

Step 1: Open the housing

To solve the problem, open the accommodation of your air filter and remove the filter. Wipeout any debris left in the filter casing.

Step 2: Clean the air filter

You can use a regular soap water mixture to clean the air filter for oil and debris.

Step 3: Dry the filter

Once cleaned, you need to make sure that the filter is dry and free of any soap residuals.

Step 4: Apply some oil

Now you need to apply the engine oil (the regular that you use) onto the filter and press it gently to reach all the pores.

Step 5: Replace if damaged

If the filter seems damaged, we recommend that you buy a new one since it’s relatively inexpensive.

5. Cleaning the spark arrestor screen:

An engine component is used to prevent fire hazards from sparks and is known as a spark arrestor. It has a metallic wire gauze that is the spark arrestor screen. The screen often becomes clogged with soot and carbon particles. It is most common when you are using the wrong engine oil.

– Solution: Cleaning the arrestor screen:

Step 1: Remove the muffler

As a solution, you need to remove the muffler or silencer cover by turning some screws.

Step 2: Clean with a brush

After carefully unscrewing the exhaust pipe assembly, you’ll notice a mesh-like screen badly clogged with oil and dirt. It can be cleaned in several ways, such as a brush or a soap solution.

Step 3: Use a torch

If available, the best method is to expose the screen to a torch or a burner until the clogs are removed.

Step 4: Reassemble

After that, you can assemble the screen back onto the exhaust pipe assembly and put the muffler back in its place.

Related Questions:

1. Electric Pressure washer won’t start: what to do?

There are several troubleshooting steps that you can try while working with an electric pressure washer. They are listed below:

– Faulty AC Outlet:

Make sure that the AC outlet you’ve plugged your machine into is working correctly. You should change the plug or the socket if it’s not working or plug it elsewhere to fix the fault.

– Problematic Power cord:

The power cord of your device might have specific faults and disconnections within that need to be checked. Look out for bends and kinks in your wire because this is where the damage will most likely be. This problem can be fixed by soldering provided you have identified the region where the breaks are. Please change your cord and get a new cable instead.

– Capacitor not working:

If your washer produces a low humming sound, it indicates that the capacitor is faulty and needs to be replaced. Since the capacitor does not store any charge, no current passes through the motor. The repair of these electrical parts is usually unnecessary since most of these components are inexpensive and are readily available. Therefore, it is better to replace them rather than repairing them.

2. How long can you continuously run a pressure washer?

It is recommended that a pressure washer should not be kept running for more than three to five minutes. The idle running time may be different for different models. The main reason that a pressure washer must not be left running inactive is that it overheats the engine. This overheating needs to be avoided at all costs since it can adversely affect the machine components’ life. Hence it is advisable to avoid leaving the engine running idle and power it off if you need to leave in the middle of the operation.

3. Can you let a pressure washer idle?

You should avoid keeping your pressure washer running idle. As you pull the cord, the engine starts, and the pump begins delivering water at high pressure through the hose.  If your machine is left running idle, i.e., no spraying of water, then this water keeps circulating within the pump under pressure. The circulated water eventually becomes hotter and hotter. Most pumps have a discharge valve, i.e., when the temperature reaches a certain degree, the hot water is released, and fresh cooler water is drawn into the pump. Nevertheless, the pump’s continuous operation with high-temperature conditions can soften the pump and hoses’ seals and O-rings. Eventually, they might wear and need to be replaced.

4. Does a pressure washer need water to start?

Although it is possible to start a pressure washer without water, however, it is advisable not to do so for increased performance of the equipment. This is mainly because the water acts as a coolant for the engine components, and without its circulation, the pump parts such as the impeller blades and the housing may heat up. This might have detrimental effects on the fatigue life of the components.

Final Remarks:

In a nutshell, pressure washing stall problems originate primarily due to insufficient combustion in the engine that is, in turn, associated with debris build up in components that deal with air-fuel mixtures, such as carburetors and filters or spark plugs and caps. To avoid such problems in the future, you should ensure that you regularly service these parts once or twice a month. Moreover, you should also make sure the engine oil is right and changed at regular intervals. Taking care of your machine will ensure not only a longer service life but will also ensure that the machine, in turn, takes care of you.

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