Gas Powered Pressure Washer Won’t Start. A pressure washer is a handy tool for cleaning many outdoor surfaces, but if it won’t start, it’s not much help. Here are a few tips to get it up and running again.

gas pressure washer won't start

A gas pressure washer can be an incredibly useful tool for improving the appearance of your home. This power equipment is great for cleaning a patio, garage floor, deck, driveway, walkway, fence, vinyl siding, or even a boat quickly and easily.

As you know, cleaning can be pretty mundane and exhausting, but using a pressure washer can make it more fun. But what’s not fun is when your pressure washer won’t start. This occurs in gas-powered pressure washers sometimes so if your gas pressure washer won’t start, don’t worry. There are several things you can do to get it up and running smoothly again.

Gas Powered Pressure Washer Won’t Start – Causes And Solution

Below is the list of some possible reasons, along with some tips on how to get your gas pressure washer back up and running again.

Pressure Washer Won’t Start: Stale Fuel

If gasoline isn’t used up in your pressure washer for more than half a year, it will become oxidized and contaminated. Old gas doesn’t have the same volatility as octane, which means it doesn’t combust properly. This can lead to low engine performance or an inability to start up at all.

Clean the fuel tank by draining the dirty and contaminated fuel, then flush the tank with carburetor cleaner. Now fuel up your pressure washer with some fresh gasoline, and make sure the fuel valve is turned on before starting it. You should also add a fuel stabilizer to help keep the fuel fresh.

In order to work safely, make sure you are in a well-ventilated area. Make sure there are no open flames or sparks around. And don’t smoke. Be sure to keep an A-B-C fire extinguisher nearby, just in case. If you have any old gasoline, be sure to dispose of it properly. Check with your local recycler or fire department to learn how to do this in your area.

Carburetor Maybe The Reason Pressure Washer Won’t Start

If your gas pressure washer isn’t working, it could be because the carburetor is clogged. The most common cause of a clogged carburetor is leaving fuel in the gas tank for more than 6 months.

Eventually, some of the fuel’s ingredients may evaporate, leaving a thicker and stickier substance. That can prevent the engine from starting, and it can be very difficult to cleanout.

If the carburetor is clogged, you’ll need to clean it out with carburetor cleaner. If this cleaning procedure does not work replace the carburetor.

Pressure Washer Won’t Start: Fouled or Defective Spark Plug

The most common causes of this problem are a fouled or defective spark plug. A fouled spark plug will have a black or sooty residue on the electrode. A defective spark plug will have a cracked porcelain body, a broken electrode, or a missing center electrode.

To clean a fouled spark plug, use a wire brush to remove the residue from the electrodes. Be careful not to damage the electrodes. If the spark plug is defective, replace it with a new one.

Pressure Washer Won’t Start due to Bad Ignition Coil

The most common reason for a pressure washer not starting is a bad ignition coil. If you are experiencing this issue, there are a few troubleshooting steps you can take to try to fix it before replacing the coil.

To do this, you’ll need a multimeter. Set the multimeter to resistance and touch the two probes to the terminals on the ignition coil. If the meter reads more than  0.5 ohms, then the ignition coil is bad and it needs to be changed

Pressure Washer Won’t Start: Broken Flywheel Key

The flywheel key is a small, metal key that is inserted into the flywheel of an engine. Its primary purpose is to keep the flywheel from turning when the engine is not running. This helps to prevent the flywheel from becoming damaged if the engine stops suddenly.

If your pressure washer won’t start, the problem is likely a broken flywheel key. This is a common issue with gas-powered pressure washers, and it can be fixed relatively easily. You will need a flywheel key puller to remove the flywheel key. Once you have the key puller, follow these steps. Here’s how to do it:

  1. Shut off the engine and disconnect the spark plug wire.
  2. Remove the flywheel housing cover. On most pressure washers, there are three or four screws that hold it in place.
  3. Inspect the flywheel key. If it’s broken, you’ll need to replace it.
  4. Use the key puller to remove it and change it.

Excessive Pump Pressure Can Cause Your Pressure Washer To Not Start

If your Gas pressure washer has an excessive amount of pump pressure, it may not start. When the pump is subjected to too much pressure, it can cause the engine to overheat and stall. This will prevent the unit from starting until the pressure is reduced.

To reduce the pump pressure, you’ll need to adjust the unloader valve. The unloader valve is a valve that allows the pump to release excess pressure. It’s located on the side of the pressure washer. When the unloader valve is open, it allows the pump to release excess pressure. When it’s closed, it prevents the pump from releasing excess pressure.

You can also do this by using a pressure regulator or by turning down the water supply. Another way is to pull the trigger of the spray gun to release pressure inside the pump.

Gas Powered Pressure Washer Won’t Start – Solutions In Video


How do you fix a gas pressure washer that won't start?

To fix a gas pressure washer that won't start:
Check the oil level If the oil level is low, add some more oil.
You should also make sure that the gas tank is full.
You may need to clean the carburetor. To clean it, you will need to remove the air filter and spray the carburetor cleaner into the carburetor.
You should also check the spark plug and make sure it is in good condition.

How do you start a pressure washer that has been sitting?

If you have a pressure washer that has been sitting for a while, you will need to perform a few preparatory steps before you can start it up:
Check the oil level. If the oil is low, add enough to bring it up to the proper level.
Check the fuel level. If the fuel is low, add enough fuel to bring it up to the proper level
Prime the pump by pulling the trigger gun several times.

Can you start a gas pressure washer without water?

It is possible to start a gas pressure washer without water, but it is not recommended. The main reason you would want to start a pressure washer without water is if you are trying to clear out a blockage in the pump. If you try to start the machine without water and there is still a blockage, it could damage the pump.

Why does my gas pressure washer keep shutting off?

There are several reasons why your gas pressure washer might keep shutting off:
A clogged carburetor is the major reason that can cause frequent engine shutdowns
If the filter is clogged, the pressure washer will not be able to get enough air and will automatically shut off.
Low fuel tanks can cause the engine to sputter and eventually shut off.
Another possibility is that the spark plug isn’t firing correctly, which can also cause the engine to stall.


There are a few things you can do to ensure that your gas pressure washer starts every time. However, if your gas pressure washer won’t start, it’s likely because of a problem with the ignition. You may also want to check and clean the spark plug and the air filter. Follow the above tips and you’ll be able to get your cleaning jobs done quickly and easily. Always take care of your pressure washer so that it lasts for years to come.

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