Simpson Pressure Washer Won’t Start – Repair Guide 2023

Simpson pressure washer won’t start – Keep patience, read my guide, and work smart

Simpson Pressure Washer Won't Start

Simpson pressure washers are one of the most durable and powerful machines on the market. The Simpson brand offers a wide variety of pressure washers that can cater to residential and industrial uses. Simpson power washers come with a wide range of features and are known for their high-quality performance.

One of the things that set Simpson pressure washers apart is their great quality Axial Cam Pump and powerful Honda and Kohler engines. Their design allows for greater longevity and durability, as well as increased power. Simpson also offers a wide variety of attachments and accessories to make your pressure-washing experience even better.

But, after all, it’s a machine and it may fall victim to any malfunction at any time due to any discrepancy or lack of maintenance. These situations can make you feel disturbed even with a new Simpson Pressure washer.

But don’t worry. Simpson pressure washer frames and parts are typically covered by a 3-year limited warranty. While its engines are usually protected by a 1 or 2-year limited warranty.

For most of the pressure washer problems, they are not so difficult to troubleshoot. With this guide for Simpson Pressure won’t start, you can troubleshoot your pressure washer at home yourself with easy fixes.

Table of Contents

Simpson Pressure Washer Won’t Start After Sitting

Whenever your Simpson pressure washer sits for too long or remains unattended for a long period of time, several problems may occur. Pressure washers not starting or not staying start is one of these problems.

We have devised this simple but comprehensive guide to troubleshoot your Simpson pressure washer for the likewise issues.

Following my guide, you can easily fix these issues at home. However, in case you are unable to fix these issues in a new machine, the warranty of the Simpson pressure washer is there to get it repaired by an authorized service center.

But first of all, before we dig deep into finding the reasons for these faults, it is important to know how to start a Simpson Pressure washer. If you are confused follow these simple steps:

How To Start Your Simpson Power Washer Properly

Electric Simpson pressure washers are simple to start. Just turn on the pressure button and the motor starts pumping out pressurized water.

However, In the case of gas-powered Simpson power washers, you must have to keep certain things in mind before starting them.

Along with these things, I will also discuss some basic steps to guide you deeply.

Below is the step-by-step guide to starting your Simpson pressure washer.

  1. Always place the Simpson pressure washer on a flat surface.
  2. Attach one end of the pressure hose to the water pump of the washer and another end to the High-pressure spray gun. Tight the spray gun and pressure the hose firmly with a wrench or any other tool.
  3. Now attach the garden hose with your water supply and pressure washer.
  4. Check both connections of the garden hose and turn on the water supply.
  5. Push the trigger of the spray gun in this state to release air or any debris in the pressure washer. Don’t leave the trigger until water begins to fall freely and smoothly.
  6. Now attach the nozzle to the spray wand. Tight it with your hand if it needs to be tightened. It’s better to attach a low-pressure nozzle first. If you have a turbo nozzle then set it to the low-pressure position.
  7. Lock the trigger at the bottom of the trigger in the OFF position.
  8. Put the choke in the “choke” position as the engine is cold and it needs a little time to become warm. When the engine warms up move the choke in to run position.
  9. Adjust the throttle lever situated on the right side of the engine to the “fast” setting.
  10. Now pull the pull string of the engine to start it up.
  11. If the engine does not start on the first attempt, do it a few more times.
  12. Now if your Simpson pressure washer is not getting near the “start”, you have some work to do. It’s time to troubleshoot it with the help of this guide about how to start your Simpson pressure washer if it won’t start.

Check this: Simpson vs Generac Pressure Washer – Expert Comparison 2023

Simpson Power Washer Won’t Start – Causes and Solutions

If your Simpson pressure washer still won’t start after following my startup guide then there must be one of the following issues.

Below is the guide to fixing any such issues which are causing your pressure washer to not start.

Spark Plug May Be The Reason Simpson Pressure Washer Won’t Start

A spark plug is the first thing to check if your pressure washer won’t start. Any signs of wear and tear or damage to the spark plug can resist the starting of the Simpson pressure washer’s engine.

Remove the spark plug from the engine for examining it.

Now check the tip or end of the spark plug for any cracks, signs of burning heavy carbon build-up, or corroded electrodes.

If there is any damage, heavy black build-up on its tip, or corrosion then it is best to change the spark plug.

But if you don’t want to buy a new one in a hurry you can just clean the plug and check if it works.

How To Clean the Spark Plug

To clean the spark plug, dip its tip in the rubbing alcohol for at least one minute.

Now scrub it with a hard brush. Clean as deeply as possible. Clean all the residue properly.

Check the gap and adjust( This adjustment is typically difficult for a newbie. So you can do it after following the manual of the machine.)

Now put the spark plug back into the engine and check the spark by putting the spark wire near the plug while starting the engine.

If there is a strong spark it means the plug is working well. However, if there is no or a low spark then it should be replaced immediately.

Simpson Gas Pressure Washer Won’t Start Due To Degraded Fuel

When you leave a gas pressure washer for more than 6 months with the gasoline in it, the gasoline will have low volatility and low octane. This oxidized and highly contaminated fuel often causes a lack of combustion ultimately causing a low engine performance or a failure to start the engine.

To resolve this issue:

  • Drain the dirty and oxidized fuel.
  • Take a good carburetor cleaner and clean the fuel tank with it thoroughly.
  • Now fill the fuel tank with fresh and good quality fuel.
  • To keep your fuel fresh add a good fuel stabilizer.
  • Now turn on the fuel valve in the “On” position.

After changing the gas, if your Simpson pressure washer is still refusing to start, move ahead to the next possible reason for resisting it starting.

Simpson Pressure Washer Won’t Start due to Clogged Carburetor

Another reason your Simpson pressure washer won’t start is due to a clogged or dirty carburetor.

Carburetors are small, precision-machined parts that help mix fuel and air for an engine to operate. When a carburetor is get clogged with dirt, dust, and other debris, it can prevent a pressure washer from starting. So sometimes if your Simpson pressure washer won’t start, the carburetor may be to blame.

Fortunately, there are a few things you can do to clean a carburetor and get your machine up and running again. The most important thing is to avoid using harsh chemicals or solvents, which can damage the delicate parts inside the carburetor.

  • One is to remove the carburetor and clean it with a small brush or pipe cleaner.
  • You can also try spraying a small amount of carburetor cleaner into the carburetor opening to dissolve the clog
  • If spraying the carb cleaner still can’t start the engine then remove the carburetor from the engine and submerge it in a container full of carburetor cleaner. Be sure to follow the instructions on the cleaner carefully.
  • If these methods don’t work, you have to replace the carburetor.

Simpson Pressure Washer Engine Won’t Start Due To a Faulty Ignition Coil

The ignition coil on the Simpson pressure washer is responsible for providing pressure to the spark plugs. When it fails, the engine will not start.

The first step in diagnosing and repairing the pressure washer with a bad ignition coil is to determine whether the coil is getting pressure or not.

To do this, use a multimeter to test for continuity between the coil’s positive (red) and negative (black) terminals.

If there is no continuity, the coil is bad and must be replaced.

The Simpson Pressure washer engine won’t start due to the Flywheel key

If everything I discussed above is in good condition the flywheel key may be the problem. But how can you check to see if the flywheel key is the problem and how can you fix it if it is?

The flywheel key is a small, rectangular piece of metal that fits into a keyhole on the flywheel. It helps to align the flywheel and the crankshaft when the engine is starting.

You can check it by removing the flywheel from the engine.

Examine the flywheel key for any damage.

If the key is missing, damaged, or misplaced, the engine may not be able to start and you have to replace the flywheel key.

The pressure washer won’t start due to a sputtering engine

If your pressure washer won’t start, the engine may be sputtering. This is due to a number of problems, including a dirty air filter, low fuel levels, or a clogged fuel line. You can troubleshoot the problem by checking the air filter, filling the gas tank, and cleaning the fuel line.

Simpson Pressure Washer won’t start due to excess pressure in the pump

If your pressure washer is not starting, it may be due to excess pressure in the pump. This can be caused by several factors, such as a clogged nozzle, a kinked hose or water that’s too hot. If the pump is not able to expel the water fast enough, it will create excess pressure and eventually cause the washer to stop working.

The best way to prevent this from happening is to keep the nozzle clear of debris and make sure the hose is not kinked. However, You can also release some of the pressure by pressing the trigger of the spray wand. Just after releasing the pressure, you can pull the cord to start your pressure washer.

What to Do if You Can’t Pull the Recoil Cord Of Simpson Pressure Washer

If the recoil starter rope on your gas pressure washer won’t pull, don’t panic. You can usually fix the problem without having to take the machine to a repair shop. Here’s how:

  1. Remove the spark plug wire from the spark plug.
  2. Make sure the water supply is turned off.
  3. Squirt a little bit of lubricant into the recoil starter housing.
  4. Pull the recoil starter rope a few times to work the lubricant in.
  5. Replace the spark plug wire and try to start the machine.

How to Keep Your Simpson Pressure Washer Running Smoothly

Pressure washers are a valuable asset for keeping your home and property clean. However, they can be expensive to replace if they break down. Here are some tips on how to keep your Simpson gas-powered pressure washer running smoothly in order to avoid damaging the equipment or causing injuries:

Inspect For Any Potential Leaks

To keep your pressure washer running smoothly it is recommended to inspect it for any leaks. Leaks can cause the pressure washer to run inefficiently and can also reduce the lifespan of the unit. If you spot any, make sure to fix them as soon as possible.

Check For Fuel and oil leaks

These are the most common type of leaks, so keep a close eye on these components.

Fuel and oil leaks are the number one cause of gas pressure washer fires. Before starting your Simpson pressure washer, check for fuel and oil leaks. Look for fuel or oil on the engine, pump, hose, or any other part of the pressure washer. If you see a fuel or oil leak, do not start the pressure washer. Repair the leak before using the pressure washer.

Check For Water leaks Before Starting The Simpson Pressure Washer

Water leaks can add up to gallons of wasted water each day that’s why it’s important to check for water leaks before starting your pressure washer.

Look for water leaks around your pressure washer, garden hose, and high-pressure hose. If you find a leak, turn off the water supply to the fixture and fix the leak.

Check the Spray Gun and Trigger

When you are using a pressure washer, it is important to make sure that the spray gun and trigger are in good condition. If they are not, you could end up with a lot of problems like low pressure or no pressure at all.

Always check the spray gun and trigger before starting the pressure washer. Make sure the trigger is in the off position and that the spray gun is tightly attached to the wand.

The trigger is the part of the spray gun that you use to control the flow of water. If the trigger is not working properly, you cannot use the machine for pressure washing.

Check the Hose and Nozzle

The next step is to check the hose and nozzle for any damage. If the hose is torn or kinked, it will restrict the water flow and reduce the pressure of the washer. The nozzle can also become clogged over time, which will limit the amount of water that is released.

Clean Machine Regularly

It is also important to clean your machine regularly. This will help keep it running smoothly and prevent any build-up from occurring. Use a mild detergent and a brush to clean all of the surfaces of the pressure washer. Be sure to rinse off all of the suds before using the machine again. washer that needs to be kept clean. To clean the house, just remove it from the unit and spray it with a garden hose. You should also check for any kinks in the hose, which can reduce water flow.

Clean The Pump

The pump is one of the most important parts of the pressure washer, so it’s important to clean it regularly. To clean the pump, simply remove the filter and spray it with a garden hose. You should also check the pump for any debris or grass that may have gotten caught in it.

Check the Oil and Fuel Level before starting the pressure washer to run it smoothly

If you are going to be using a pressure washer this summer, it is important to check the fuel and oil levels before starting it. This will help to ensure that the pressure washer runs smoothly and does not overheat.

Check Fuel Level 

In order to check the fuel level, locate the fuel cap on the pressure washer. It is usually located on the upper part of the machine. Once you have found the fuel cap, remove it and look inside. There will be a fuel gauge or indicator on the pressure washer that will tell you how much fuel is left in the tank.

If the fuel level is low, fill the tank with fresh gasoline.

Check Oil Level 

When you are finished using your pressure washer, you should always check the oil level before you start it up again. This is to ensure that the pressure washer will run smoothly and that you won’t damage the engine.

The oil level should be checked every time you use the pressure washer. You can find the oil level dipstick on the side of the engine. The oil level should be between the two marks on the dipstick. If it is not, you will need to add more oil. Be sure to use the type of oil specified in the owner’s manual.

Check and Clean Air Filter To Run Pressure Washer Smoothly

Air filters should be checked and cleaned often to keep the Simpson pressure washer running smoothly. If they are not kept clean, the air filter will become clogged and the pressure washer will not work as well.

A dirty air filter reduces the amount of air that reaches the engine, which can cause the pressure washer to run poorly and could eventually damage the unit.

To clean the air filter, remove it from the pressure washer and gently tap it against a hard surface to remove any large debris. Then, use a vacuum cleaner to remove any smaller particles. Finally, spray the filter with a light coating of oil to keep it moist. It is important to note that the air filter should not be soaked in water, as this will damage it.

Moreover, an air filter is highly prone to dirt and debris and often requires a replacement. Just cleaning it won’t help sometimes so replace it with a new one whenever required.

Other Measures To Always Start Your Simpson Pressure Washer Smoothly

  • Always use the correct nozzle for the job. Trying to use a high-pressure nozzle on a low-pressure job will damage the washer and could potentially void the warranty.
  • Be sure to keep the pump oiled. This is a critical step that many people forget. If the pump isn’t oiled, it will overheat and eventually break down.
  • Start the engine and allow it to run for a few minutes to warm up, especially in colder weather.
  • Press the trigger gun and hold it down to release the pressure in the pump before starting.

What causes a gas pressure washer not to start?

There are a few things that could go wrong with your gas pressure washer that would prevent it from starting. It’s possible that there is no fuel getting to the engine, the ignition system isn’t functioning, the air filter is clogged, or there is an issue with the carburetor.

  1. If you suspect that there is no fuel getting to the engine, check to make sure the fuel tank is full and that the fuel hose is connected properly.
  2. In case, the ignition system isn’t functioning, you may need to replace the spark plug or the entire ignition module.
  3. If the air filter is clogged, you can remove it and clean it or replace it if it’s damaged.
  4. If there is an issue with the carburetor, you may need to have it cleaned or replaced.

Can you start a gas-pressure washer without water?

No. You should not start a gas-pressure washer without water. You always need to make sure you have enough water available to operate the pressure washer. If you don’t have access to a water supply, you won’t be able to use the machine.

The other thing to keep in mind is that gas-pressure washers can be dangerous if not used correctly. Make sure to read the manufacturer’s instructions carefully and follow them closely.

What is an unloader valve in a pressure washer?

The unloader valve on a pressure washer is responsible for controlling the flow of water. When the unloader valve is open, it allows the high-pressure water to escape. When it is closed, the water builds up in the pump and creates more pressure.

Where is the unloader valve on a pressure washer?

The unloader valve is a critical part of the pressure washer that helps to regulate the pressure. It is located on the side of the machine, near the pump. The unloader valve allows water to flow back into the water tank when the trigger is released. This prevents the pump from being overloaded and protects it from damage.

How do you know if your unloader valve is bad?

There are a few telltale signs that your unloader valve is bad. If you notice that your machine is leaking oil, that’s a clear sign that there’s a problem with the unloader valve.

Also, if you find that your machine is having trouble maintaining a consistent oil level, or if it’s taking longer than usual to bring the pressure up to the desired level, those could also be signs that your unloader valve needs to be replaced.

How do you remove a stuck unloader valve?

If your unloader valve is stuck, you will need to remove it in order to clean it or replace it. The process is not difficult, but it can be a little messy. Here is a step-by-step guide on how to do it:

  1. Shut off the power to the machine and unplug it.
  2. Remove the screws that hold the cover of the pump in place.
  3. Disconnect the hoses from the valve.
  4. Remove the valve.
  5. Clean or replace the valve as needed.
  6. Reconnect the hoses and reattach the cover.
  7. Power on the pressure washer and test it.


Simpson pressure washer is a solid machine but any negligence on your part can stop it from starting properly or maybe it won’t start when you want it to.

Maintaining your Simpson pressure washer is important to ensure its safety, performance, and long life. I hope this article will help you on how to properly maintain your pressure washer so that you can’t face the issue of not starting anymore. Follow the above tips to keep your pressure washer in good working condition and get the most out of it.

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Flinn Milan

Flinn Milan is the content director at Washwith. He is responsible for developing helpful content in collaboration with other hard-working team members. Over several years, his content strategy is mainly focused on describing and highlighting every product with its positive and negative points

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