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Karcher Pressure Washer Won’t Start, Stop, Stay On, Etc

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If you feel like you are spending too much time cleaning, the thought has probably crossed your mind about how to make your life easier. One idea that you have been kicking around is investing in a pressure washer to quickly do all of those tedious cleaning chores that used to take you hours, so you go out and buy a new Karcher pressure washer.

How do you troubleshoot issues with your Karcher pressure washer? There are a number of common issues that may arise over the course of your Karcher pressure washer’s life. As an owner, it is important to know what to look for and some possible quick remedies before giving your Karcher pressure washer up as finished.

Karcher Pressure Washer Won't Start, Stop, Stay On, Etc

While there are some issues that may require an experienced repair person to fix, many problem areas can be troubleshot simply by following the steps outlined in this article. By checking off the items on this list first, you are likely to save on professional repair costs or having to get a new Karcher pressure washer altogether.

Karcher Pressure Washer Hose Won’t Stay On

Man with hands up in frustration

When operating a Karcher pressure washer, you will be dealing with two hoses.

  • The first hose is your typical garden hose that connects the water source to the pressure washer’s input port. 
  • The second hose comes with your Karcher pressure washer and is reinforced to withstand the pressurized water that leaves the pressure washer from the water outlet port to be sprayed on the cleaning surface. 

While it is rare that you will ever have issues with the garden hose that connects to the water source, the pressurized water leaving your Karcher pressure washer can expedite the wear and tear process on your spray hose at the outlet connector and sometimes, this hose will begin to disconnect from the pressure washer when in use.

Beware of the temporary fix

Quick, temporary repairs involve using duct tape, silicone self-fusing repair tape, or a well-positioned c-clamp to secure the high-pressure hose to the water outlet port. These remedies can have varying levels of success in the short-term but often lead to lower performance in your Karcher pressure washer and make storage in between uses inconvenient.

As the most likely cause of a hose that will not stay on your Karcher pressure washer is worn threads at the water outlet port, the remedy that will lead to the most sustained success and optimal performance of your Karcher pressure washer is a complete replacement of the water outlet port.

Replacing the Water Outlet Port

While this sounds like a scary repair, it is quite simple to do yourself if the following steps are followed:

  1. Purchase a replacement water outlet port – this is a small, plastic part that can be found at most home improvement stores or online for about $10.
  2. Remove the covers – there is a top cap and front cover that must be removed, in that order, in order to get to the origin of the water outlet port on the inside of your Karcher pressure washer. There are some screws on the top and back that secure these covers, so carefully remove the screws and put them in a safe place as you take the covers off.
  3. Disconnect the water outlet port – this port will be connected to the water pump with a metal fork and an o-ring. The fork needs to be pulled out of the port (you may need to use some pliers to do this) to unfasten the port from the pump. Then slightly lift the pump and pull the port away.
  4. Transfer the o-ring – take the o-ring out of the old port and give it a thorough inspection. If it is damaged, obtain a new one. If it looks good, put it into the new port, making sure that it is snugly embedded to create a tight seal.
  5. Connect the new port to the water pump – slide the replacement port onto the water pump, making sure it is snugly in place and facing the correct direction. Once in place, reinsert the metal fork to secure the connection between the water pump and port.
  6. Replace the covers – now that the replacement water outlet port is installed; it is time to replace the covers of your Karcher pressure washer. Make sure everything is flush and properly aligned before reinserting the screws that hold the covers in place

Your Karcher pressure washer should no longer have an issue with a hose that will not stay on. On the off chance that you are still having connectivity issues with your hose, the hose itself may be damaged, and you may need to look into purchasing a new high-pressure hose.

Karcher Pressure Washer Won’t Start

Yellow pressure washer spray

There is nothing more disheartening than plugging your Karcher pressure washer in, getting all of the hoses connected with everything set up for cleaning, and turning the power switch on–only to be met with a vacant “click.”

The reason behind your Karcher pressure washer’s failure to start is most likely very simple and can probably be identified yourself without having to consult an expert.

Check the Outlet

It is common nature that when an appliance does not turn on to think that there is something wrong with the appliance itself.

However, the issue most likely has something to do with the power source.

Unplug your Karcher pressure washer and plug in an electrical appliance that you know to be working, such as your cell phone charger. If your cell phone does not charge, look around for a switch. Some buildings, especially older garages and other outbuildings have switches that connect to an outlet, much like regular light switches control overhead lights.

If the switch to the outlet is on and/or you have discovered that there is power coming from the outlet, but your Karcher pressure washer still will not start, you may be looking at one of the other issues on this list.

Switch Extension Cords

There is a very high likelihood that you are using an extension cord with your Karcher pressure washer, as most of the hard to clean places around a property are not conveniently located near an outlet.

Just like you did when checking the outlet, you will want to check your extension cord and see if it is supplying power, so if you have a shop vac or electric weed eater handy, plug it into the extension cord and see if it fires up.

If other electric appliances are working with your extension cord, then there could be a compatibility issue with your washer. While you should be fine using any extension cord, Karcher pressure washers are known to perform better with a 25-foot 12/3 gauge cord or a 50-foot 10/3 gauge cord.

Try using one of these specific cords and see if you have any luck.

Clear the Air from Your Hoses

Air in the hoses of your Karcher pressure washer can cause myriad issues, as you will see as you read through this article. However, one of the features unique to Karcher electric pressure washers is that if the washer detects air in the system, your unit will not turn on. 

Hoses filled and blocked with air can cause problems in your pressure washer that, when left unattended over time, can irreversibly damage your appliance’s functionality. To combat this, most Karcher pressure washers simply will not turn on if there is air in the system.

To combat this issue, take the following steps:

  1. Ensure that your water source is turned off.
  2. Securely attach the garden hose to the water input port and the high-pressure hose to the water outlet.
  3. Remove the spray wand from the end of your high-pressure hose.
  4. Keeping your Karcher pressure washer turned off, turn on the water source and allow regular, unpressurized water to run through the system for at least five minutes.
  5. Turn the water source off, reconnect the spray wand to the end of the high-pressure hose, and do this process again, only this time, pull the trigger on the wand tip to remove any air blockages from there. Do this for about five minutes, as well.
  6. After doing both of these unpressurized runs, switch your Karcher pressure washer on. Now that all air pockets have been removed from the system, your washer should successfully start

Check for Electrical Shortages

In the unlikely event that none of the aforementioned remedies gets your Karcher pressure washer to power on, you are probably looking at an electrical shortage in the switch or the washer’s motor.

While uncommon, electrical shortages can be caused by trauma to the unit, old age, or getting excessive water introduced into areas that are meant to be kept dry.

You will need to use a multimeter to see if the electrical holding capacities are within range for your unit and if you want to attempt a do-it-yourself repair for an electrical issue you identify, some specific, in-depth steps can be found in this helpful video.

Karcher Pressure Washer Won’t Stay On

Pressure washer red nozzle

A Karcher pressure washer that will not stay is most likely influenced, to a lesser extent, by the same issues that cause the unit not to start. As such, run through the following checklist:

  • Make sure the outlet or power source is turned on and functioning at full capacity
  • Try switching extension cords 
  • Run regular water through the system to remove any air pockets
  • Use a multimeter to check for issues that may be causing electrical glitches

While any or all of these factors could be causing your Karcher pressure washer to randomly die, the most likely cause of this particular problem is incompatibility with extension cords

Just as some aftermarket charging cords do not always charge your cell phone, certain extension cords, especially extremely long versions, do not provide a consistent power supply to your Karcher pressure washer. Make sure to try a 25-foot, 12/3 cord before taking any more drastic measures.

Karcher Pressure Washer Won’t Pressurize

Pressure washer on wood deck

As mentioned earlier, electric models of Karcher pressure washers will not turn on if they detect inappropriate pressure levels as a safety mechanism to protect the longevity of the unit.

However, if you are using a gas version, or have an older electrical model that may be suffering some glitches with its bells and whistles, then you may run into a scenario in which your pressure washer is running, but the water it is spraying is not as highly pressurized as what you would expect. There could be several reasons behind the low-pressure output:

  • Blockages in the nozzle tip – sometimes, dirt and grime can accumulate in the nozzle tip, especially if your Karcher pressure washer has been sitting for long periods between uses. As the opening in the nozzle tip is extremely small, any clogs can greatly influence the amount of pressurized water released. Remove the tip and clean thoroughly.
  • Leaks in the hoses – carefully observe both the garden hose and high-pressure hose to see if there are any leaks or kinks that could be inhibiting the flow of water to or from the unit.
  • Clogs at the ports – remove both the garden hose and high-pressure hose, checking both the input and output ports for any caught debris that could be impacting the low of water.
  • Worn out nozzle – your Karcher pressure washer should come with a variety of nozzles meant to perform an array of functions for specific cleaning jobs. However, there is a tendency for owners to use the same nozzle for everything, which could cause the nozzle to wear out after significant use. Switch nozzles and check the pressure.
  • Air trapped in the water pump – using the same process you did for clearing air pockets out of the hoses, run some unpressurized water through the unit for several minutes to clear your Karcher pressure washer of any excess air that could be affecting pump performance.
  • Internal leaks – in some rare instances, there may be a leak coming from internal components of your pressure washer. Using the same process you used for changing the water outlet port, remove the covers of your unit and run some regular pressure water through the pressure washer, making a note of any water spraying in odd places.
  • Low GPM – pressure washers are rated to run a certain GPM (gallons per minute) of water through the pump. A common GPM rating is 3.0. Therefore, if you are running less than 3.0 GPM through the system, the pressure at the output will be low. Check your water source and see if it is able to provide the appropriate GPM for full function.
  • Failing water pump – this is by far the most serious issue with a Karcher pressure washer that is not providing pressurized water. While old age and abuse can lead to water pump failure, the most common reasons that a pump will fail are due to continued low-pressure output or continued low GPM received at input.

In order to avoid a costly water pump repair, do not run your pressure washer if you detect it is not functioning at optimal output. Turn your unit off and locate the reason behind the low pressure before attempting further use.

Karcher Pressure Washer Won’t Stop

Guy pressure washing house wall

On rare occasions, you may encounter a scenario in which you have switched your Karcher pressure washer off, but the unit continues to run.

This is likely due to continued exposure to low pressure. When the unit detects that it is not functioning the way it should, it may continue running to overcompensate for the lack of output.

Once again, this is another reason why it is essential to know what the optimal PSI (pounds per square inch) output of your Karcher pressure washer is and avoid running it when the pressure output is not at the appropriate level.

Karcher Pressure Washer Won’t Spray

Man with arms and hands crossed

Failure to spray is almost always related to an issue with the nozzle. To check to see if your nozzle is in good condition, take the following steps:

  1. Remove the nozzle tip – this will be a small, plastic piece at the end of the spray wand. It should easily pop out from the wand’s end with a moderate pull.
  2. Check the water release hole – holding the nozzle tip up to the light, check to see that light is able to shine through the small hole in the nozzle tip. If not, take a pin or small piece of wire and poke away any debris that is clogging the hole.
  3. Reattach nozzle tip and spray – once the clog is removed from the nozzle tip, your unit should be able to spray at optimal levels again

If the unit is still not spraying after cleaning the nozzle tip, switch out with different nozzles to see if your Karcher pressure washer will spray with other nozzle settings.

Continued failure to spray is likely caused by the same issues that lead to low-pressure output, so make sure you are checking for leaks and blockages in your hoses and pressure washer.

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