Your pressure washer won’t start or won’t stay running?

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Your pressure washer is an incredibly useful tool for taking care of those tough stains fast. I find it an incredibly handy weapon to have in my arsenal in my fight against dirt and grime.

I love being able to grab my pressure washer out of my garage and start cleaning within minutes, well, I did.

Sometimes when you pull it out, you find that your pressure washer won’t start, won’t crank, or just plain won’t stay running.

So, what do you do if your pressure washer won’t start, crack or stay running?

Firstly, you will have to troubleshoot your pressure washer to work out where the problem is. If it’s an electric pressure washer I first check to see if the power supply is working, perhaps trying another outlet. If it’s a gas pressure washer, I make sure that the gas is fresh. I then check to see if there is any old sticky gas clogging up the carburetor. I move on to check the spark plugs are working and correctly gapped and that all the filters are clean, such as your air filter. Finally, I look for leaks.

While your pressure washer seems like a simple machine, it’s actually a rather complex machine. Many components working in tandem with each other to make the machine function properly.

Some of the basics for a successful function, the easiest one being, the pressure washer much be turned on, this can be easy to overlook for an electric pressure washer, i.e., did you switch on the outlet?

What to Look for and How to Start It

What To Look For And How To Start It When Your Pressure Washer Wont Start

When you start troubleshooting your pressure washer, the easiest thing to do is eliminate some things right out of the gate. These are easy to identify depending on how you’ve found the machine, which can help focus your search.

Suppose your pressure washer has been sitting for a long time. In that case, the gas might have become stable, broken down, and potentially clogged up the carburetor.

If it won’t fire, it could be the spark plug or even the ignition coil.

If it starts fine but then struggles to idle or just plain won’t stay running, it may be because the air-fuel ratio may be off. This could be because the gas and air filters are clogged.

Start by Checking the Basics

Before you dig into the complex problems, I suggest you check to ensure you aren’t overlooking something basic first.

So check the following:

  • Is the pressure washer plugged in (if it’s electric) or have enough fresh gasoline (if it’s gas-powered).
  • Turned on (started if gas, outlet, and power switch if electric)
  • Is there enough oil (gas only)
  • Properly connected to a water source that’s turned on and feeding the correct gallons per minute. 
  • The inlet hose has no kinks and no links in the hose.

Once you’ve checked these basic’s only then can you begin to investigate more specific issues that may cause your pressure washer to not crank, or your pressure washer won’t start or stay running.

Winterize a Pressure Washer

Gas-powered pressure washers have a gasoline engine that powers the pump. Like any other garden tool that features an engine that sits idle all winter (such as your lawnmower), it needs to be properly winterized to avoid suffering damage during the cold months.

When it comes to winterizing a pressure washer, you need to make sure that all the tanks are completely drained of water and detergent. When water freezes, it expands. Any water left in your pressure washer pump could end up expanding enough to cause damage to the internal components. Water can also damage the tanks or even the hoses.

You should also drain the gas out of your gas-powered pressure washer before you store it in your garage during winter.

Not only is there a risk of expansion, but the gasoline can break down and become stale over the months it sits in storage. Your gasoline can also separate into its component ingredients, which isn’t ideal. When the less viscous liquids evaporate, you are left with a thick tar-like substance that can clog your washer’s carburetor.

Check the washer’s Spark Plug

Inspecting your pressure washer’s spark plug is always a good place to start because these are easy to get to, easy to inspect, and cheap and very easy to replace. Simply locate and disconnect the terminals from the plug and unscrew it; you may need a socket wrench for this.

Give your spark plug a visual inspection. Often this is enough to determine if the spark plug is the problem. With just your naked eye, you can see if:

The porcelain insulator is damaged.

Whether or not the electrode has a heavy carbon deposit build-up or if it’s in disrepair.

If either exists, you can attempt to clean or replace it entirely.

Even with a visual inspection passing, your spark plug could still be the problem. You can get a special took to check whether or not the spark plug is working and generating a spark.

When the engine cranks, you should see a strong spark between the tester’s terminals. If there is no spark, then you’ll need to replace the spark plug.

If there is a spark, then your spark plug is working fine.

Check that all the connections are in place and as well secured.

Check the Ignition Coil

If you’ve proven that your spark plug is working, the problem could be the ignition coil. This is what sends the voltage to the plug while the engine is running. A defective ignition coil could prevent your power washer from starting.

You can test the ignition coil with an ignition coil tester. If you find that it’s defective, then you’ll need to replace it. If your spark plug and ignition coil are both working, then the problem is likely elsewhere.

Check the Carburetor

If your pressure washer won’t start after winter, there is a very good chance that the problem is with the gas that you accidentally left in the gas tank/fuel tank. Over time gasoline becomes stale. It can also become thick and sticky, clog your carburetor, which will cause the engine not to start.

If this is the problem you are suffering from, then you may have to clean the carburetor with a carburetor cleaner, which is specially designed to break down this kind of sludge. If this doesn’t work, you may need to entirely break down, clean, and rebuild your carburetor. Worse case, you may need to purchase a new one.

Even if the gas isn’t clogging your carburetor, it could just be old. It will become sticky and tar-like aft a few months, but it’ll start to go stale after only a month. So when possible, you should use fresh gasoline, and nothing older than 30 days.

Checking your power washer When the Water is On

Checking The Washer When The Water Is On

Your pressure washer has a pump that takes water from your garden hose and pressurizes it to a high pressure, creating water pressure strong enough to clean surfaces.

Some pressure washer pumps will not start unless they are primed, which means that the inlet hose needs to be full of water and no air pockets. Sometimes having air in the hose will prevent the pressure washer from starting.

Check That the Pump is Primed

To make sure that your pump is primed, you can follow these simple steps to prime your pump.

  1. Connect your garden hose to your pressure washer and turn on the water fully. 
  2. Connect the high-pressure hose and spray wand. 
  3. Pull the trigger on your spray wand to allow water to flow through the power washer; this will remove any trapped air. 
  4. With the water running, hold the spray wand’s trigger open with one hand (pull the trigger), keep the wand pointed away from you and others and in a safe direction, then start the engine. This may require some help from a friend. 

This should prime your pump removing any air pressure from the hose and resulting in the engine starting.

When you’ve finished using your gas-powered pressure washer or electric power washer, remember that the hose will still be filled with high-pressure water, you can release it. You should release it before storing your pressure washer.

Here are the steps to do that:

  1. Turn the engine off.
  2. Turn the water supply off and disconnect the garden hose.
  3. Hold the trigger down on your spray wand to release the pressure.
  4. Disconnect the wand and hose and drain the water out before storing.

Checking the washer Isn’t Out of Gas

White Gas Tank Illustration
White Gas Tank Illustration

Before you start the pressure washer, check that the tank actually has gasoline in it. Perhaps your power washer was working fine, and you were in the middle of removing a stain from our driveway, perhaps cleaning the siding of your house. You were about to start cleaning your deck when suddenly it cuts out.

This could be a simple fix; simply put more gas into your tank, start it up and continue as you were.

Perhaps you’ve refilled the tank, and the pressure washer won’t start. Wait, what?

Check the Fuel Pump

If you run your pressure washers tank completely out of gas, you may find that putting fresh gas in isn’t enough to get it to start again. This is because those final dregs of fuel may be old and dirty, which ends up clogging up your carburetor; the end result is that you’ll need to replace or rebuild the carburetor.

Some fuel pumps are cooled down by the fresh gasoline that flows through them. When your pressure washer runs out of gas, the fuel pump ends up overheating, which can lead to damage and result in it needing to be replaced.

There’s a technique called “wetting the bowl,” which can be used to get your pressure washer started again.

To do this, remove the plug, put about a tablespoon of gasoline or even lighter fluid into the socket, replace or reattach the plug and attempt to start it. Sometimes wetting the bowl in this way is enough to get it started again after your fuel pump has burned dry.

Checking the pressure washer after it has Been Sitting around for a While

I don’t know about you, but I find it hard to do something I haven’t done in a while, just remembering those little steps. This is the same for pressure washers as it is for people.

If you are troubleshooting why your unit isn’t starting, it could just be that it just needs a few attempts due to how long it’s been sat around.

Try a Tune-Up

I like to start spring with a tune-up of my various outdoor equipment; this means that I:

  • Make sure that the fuel and air filter are clean
  • Test for the plug and that the ignition coil is working
  • Check the flywheel key
  • Check the oil levels
  • Look for any leaks or any visible damage
  • Check the carburetor to see if it’s clogged, and clean or replace it. 

Even when in use, your sitting pressure washer is prone to a range of wear and tear.

Check the Carburetor

If you’ve left your pressure washer to sit around for a while, it’s worth taking some extra time to check over the carburetor. If you’ve left fuel in the engine, it may have deteriorated over that time, and when it goes stale, it can leave a thick sticky goo, which loves to get your carburetor all clogged up.

If this is a problem with some simple tools and a cleaning solution, you can easily repair your carburetor, just open it up, clean out the blockage with some carburetor cleaner. Though do not use this if your carburetor’s needle valve tip is made from rubber, as the valve will be corroded by the cleaner.

If this doesn’t work, you’ll need to rebuild, repair, or even replace your carburetor.

Checking the pressure washer when it gets too hot

Cleaning Terrace With A Pressure Washer
cleaning terrace with a power washer – high water pressure cleaner on wooden terrace surface

A fantastically frustrating problem is that your pressure washer starts fine when cold and will work for a while.

Then you shut it off for a few minutes and come back and attempt to start it up, and it just won’t start while the engine is hot or even warm. You give it an hour, the pressure washer cools down, and then starts up without a worry.

This is incredibly frustrating, but here are a few things to check.

Check the Carburetor Screw Settings

Your pressure washer’s engine’s carburetor is responsible for the air-fuel ratio. It handles the mixing of these at the ratio for your engine to run properly.

If there is too much fuel and not enough air, the fuel won’t burn as oxygen is needed.

If there’s too much air and not enough fuel, the engine won’t run as there isn’t enough fuel to burn and create force.

Asides from your carburetor getting clogged from old sticky fuel, the screws could be adjusted to the wrong settings. These screws need to be in balance, and that balance is very delicate; if you’ve got it wrong, the engine may start fine when cold, but once it warms up, metal expands. It’s enough to throw off your ratio, resulting in pressure washers not starting.

You can adjust your pressure washers, engines carburetors mixture screws with some simple tools, well just a screwdriver, really.

These screws are very sensitive, and turning them even a quarter of a turn will have dramatic effects. Finding the correct balance is, unfortunately, a long process that involved lots of trial and error, but that trial and error can save you a lot of money if it means you don’t need to replace your entire washer.

Check the Exhaust Valve

Sometimes your pressure washer can get quite hot during use, and again metal expands, and it can expand enough that the exhaust valve gets stuck open; this is one of those rather rare problems that are hard to diagnose. Replacing the exhaust value usually solves the problem.

Checking pressure washer after it has been in storage for a while

Checking Washer After it Has Been in Storage For a While

Any time you take a pressure washer out of storage when it’s been stored for a while, you may need to give it a quick tune-up.

If you find that your pressure washer won’t start after it’s been in long term storage, there are a range of things that may have gone wrong; like any old piece of machinery, they work best when they are used regularly.

Try a Tune-Up

First things first, make sure everything is in working order. Check the plugs, make sure it’s filled with fresh gas, and the right amount of fresh oil.

Check the Carburetor

If you’ve stored your pressure washer, you should have drained all of the fuel out of the system. If you haven’t, you may find that the gasoline may have broken down, which results in it becoming sticky, which will cause your carburetor to become clogged; if this is the problem, just give it a clean.

Checking the washer After it Has Been Running

I find nothing more frustrating than when my pressure washer suddenly stops working. If you’ve been pushing your washer and find that it stops working, then the solution could be easier than you think.

Check the Flywheel Key

Your flywheel key is a rather small piece of metal that engages the flywheel, which sits inside the washer’s crankshaft.

This item is designed to shear in half if the pressure within the crankshaft becomes too high. This is a protection mechanism to prevent any overexertion within the system. Perhaps you’ve been wet sandblasting for a long time, and everything is overheating.

Because it’s designed to break, easy to check, and very simple with a few tools and some replacement parts to replace the flywheel key. Within minutes you’ll have a working machine again.

Checking When Washer Won’t Stay Running

Sometimes your pressure washer will start up just fine, but it won’t continue working after a short period of use. This gives you a different suite of problems to start troubleshooting.

Check the Fuel Cap

As your pressure washer runs, gas is pumped out of the gas tank, passed through the carburetor, and burned in the engine to power the pump. As the gas leaves the air, air needs to replace the void. This air enters through the fuel cap. If the fuel cap is clogged, the air cannot vent in. To check that this is your problem, try running the pressure washer with the fuel cap slightly unscrewed, allowing air to seep in. If the engine continues to run, simply clean or replace the fuel cap entirely will fix the venting problem.

Check the Fuel Filter

I’ve mentioned a few times how old gas can become sticky, and this thick tar-like sludge can clog up your pressure washers carburetor. To prevent this, the fuel will pass through a fuel filter. While this may save your carburetor. The fuel filter itself may end up getting clogged, which will starve the engine. Clean or replace the fuel filter.

Check the Air Filter

Your carburetor mixes fuel and air to a ratio that is perfect for your engine. Your air filter keeps debris out of this mix, and it can become dirty and blocked. This is a cheap part to replace. If you don’t get enough air to the engine, the engine can stall, so a quick troubleshooting step is to replace the air filter and see if the problems still exist.

Check the Spark Arrestor

Your pressure washer’s engine may have a spark arrestor. This is a small screen that is designed to prevent the engine from emitting sparks. Just like your fuel and air filters, it can get clogged up. Give this a quick clean with a wire brush or replace it entirely.

Wrap Up

If your pressure washer is having any issues, hopefully, these simple steps will help get it up and running quickly. Sometimes just a simple oil change is all that’s required.

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