Pressure Washer Stalls When Trigger Is Pulled: Reasons and How to Fix

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If your Pressure washer stalls when trigger is pulled, this article will help you find the problem and fix it.

What causes the pressure to turn off? How do you fix this problem?

When you need to do a thorough cleaning in your home, a pressure washer comes in handy, especially in parts that are hard to reach.

It cleans stubborn dirt and mud in the walkways, building walls, cars, and paving thanks to the pressurized water.

However, you cannot achieve this if the pressure washer is not functioning properly.

Check my post on best garden hose for a pressure washer.

Knowing how to fix a faulty pressure washer is an advantage and saves you the effort and money of having to call a professional.

In this article, I will discuss why the pressure washer stalls when trigger is pulled and how to fix them.

Reasons and Fixes on Pressure Washer Stalls When Trigger Is Pulled

You will require the following tools; screwdriver, wrench, and grease.

1. Inspect the Unloader valve

In most cases, the unloading valve of the pressure washer is the cause of problems.

It diverts the flow of water into a loop once the pressure washer trigger is released.

The unloading valve regulates the pressure of the machine to give a steady flow of water.

If the pump’s pressure surpasses that of the engine, the engine will start moving and stalling.

When the valve accumulates dirt around the spring, O-ring the pressure washer starts having problems.

In this case, adjusting or removing the pressure washer unloader valve is required.

Also read on lawn mower valve adjustment symptoms.

2. Remove the Unloader Valve

With the use of a screwdriver and wrench, remove the valve from the bay.

Lock the unloader valve in its bay using the valve-retaining pin.

A retaining valve is usually U-shaped; once you locate it, insert a screwdriver in, and then pull it out while unscrewing.

Make sure you don’t use a lot of force while unscrewing.

Note that both pressure–actuated and flow-actuated unloaders are removed using the same procedure.

3. Check if there are problems with unloading valve

The O-rings, piston, or the unloader valve’s settings may be the reason why your pressure washer stalls when the trigger is pulled.

Check those parts to find out if they are working out properly since they may cause the problem.

4. Check the carburetor

The main work of a carburetor is to mix air and fuel in the combustion engine.

The most common problem with the carburetor is loosening or clogging.

If your carburetor is clogged, clean it by draining the gas tank, and if loose, tighten it.

In case both tightening and cleaning does not fix the problem, then it is time to replace your carburetor.

Which side of lawn mower blade is up?

5. Inspect piston

The piston is a part of the unloader valve, and its work is to control the machine’s pressure.

Once the pressure washer is on, the piston moves backward, then forward, and if its movement is interfered with, the machine stalls.

Inspect the piston if your machine turns off after the trigger is pulled.

6. Adjust the unloader valve settings

The pressure released by the pressure washer depends on the object or surface or the cleaning you are doing.

When the settings are too high, the pressure washer tends to shut down.

Ensure the settings you choose to allow the unloader valve to open up to cycle water to the inlet to avoid pressure build-up.

How to adjust the unloader valve

First, ensure that the engine is running before you start the adjustments.

Turn on the outlet valve until all the air is out and water starts coming out.

Make the pressure spring tight as you choose the pressure of your preference.

Keep on moving the lock nuts

Make the trigger go off, then return the washer, pressure spring, and the lock nuts in position.

7. O-rings

Even when the unloader valve effectively functions in the right settings, the pressure washer might still stall.

Check out for the O-rings since they might be worn out.

O-rings’ main function is to seal the oil pump, so once they wear out, the sealing does not take place; thus, the unloader valve does not function as required.

The solution to this is to replace the old rings with new ones so that there is no leakage in the oil pump.

Grease, thread tape, and grease cleaner will help in to install and reinstall the rings.

8. Check the Pressure gun

Pressure Washer Stalls When Trigger Is Pulled

A pressure gun needs regular servicing for good maintenance.

If you take too long before servicing it, your pressure washer may not function effectively.

Even after fixing all the above pressure washer parts, the machine will still shut down if the pressure gun is not in good condition.

Check my post on the top 7 best electric grass shears

To fix this problem, service the pressure gun or consider purchasing a new one.

In case all the above does not solve the problem and the pressure washer still stalls when trigger is pulled, try the following.

  • Clean the spark plug using alcohol and inspect if it is disconnected.
  • Release pressure or air from the machine’s system.
  • Check the water supply and ensure there is an adequate flow to the pump.
  • Take the air filter out and clean it using a dry cloth since a dirty air filter causes inadequate pressure regulation.
  • Check the oil levels and refill if they are low.
  • Inspect the wand screen.
  • Switch off the choke position if you notice the engine is smoking.

If you’ve tried all the above and nothing seems to change then it’s time to purchase a new pressure washer.

Your pressure washer may be old such that most of the parts are worn out and are not functioning properly.

I would recommend GreenWorks 1600 PSI 13 Amp pressure washer

Final Thoughts On Pressure Washer Stalls When Trigger Is Pulled

Always take the safety precautions when operating.

You now know the reasons why the pressure washer stalls when trigger is pulled.

Having a faulty pressure can make cleaning a very boring activity.

Even if you buy the best pressure washer in the market, it can still develop some problems over time.

Ensure you service, clean, and inspect your pressure washer regularly for the proper functioning of your machine.

Additionally, it is important to take good care of the machine and keenly go through the manufacturer’s manual.

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