Karcher pressure washers are pretty reliable and offer an excellent solution for cleaning various surfaces. Despite the utility, even some of the best pressure washers can develop problems that need to be identified before they can be fixed. The pump and the water delivery system are critical aspects that must be heeded for the smooth working of a pressure washer.
If a Karcher pressure washer leaks water, check the connections at the pump, high-pressure hose, and spray gun. Ensure that these connections are tight and that the seals and O-rings are fully intact. If the water pressure isn’t ideal, check the nozzles for any blockages and adjust the unloader valve to an optimum setting. If your pump gives off noise or leaks oil, make sure its seals aren’t worn out, and the pump is being lubricated timely.
In this blog post, I will show you how to troubleshoot issues related to the pump and water delivery system for Karcher pressure washers and perform their fixes by yourself.
Contents
- 1 Karcher Pressure Washer is Leaking Water
- 2 Karcher Pressure Washer: Water Pressure Problems
- 2.1 1. Karcher Pressure Washer: Low Pressure
- 2.2 2. Karcher Pressure Washer: No Pressure
- 2.3 3. Karcher Pressure Washer: Surging Pressure
- 2.4 4. Karcher Pressure Washer: Drops Pressure after a Few Seconds
- 2.5 5. Karcher Pressure Washer: Strange Noises from Pump
- 2.6 6. Karcher Pressure Washer: Excessive Noise
- 2.7 7. Karcher Pressure Washer: Oil Leaking from the Pump
- 2.8 8. Karcher Pressure Washer: Water in Oil
- 2.9 9. Karcher Pressure Washer: Soap Not Dispensing from Reservoir
- 3 Troubleshooting table for a Karcher Pressure Washer
Karcher Pressure Washer is Leaking Water
Your Karcher pressure washer may leak water from one of the connections. To troubleshoot the water leak, you need to check its connections at the pump and spray gun separately.
Usually, there are three connections from where a leak is likely to occur. The first location is the pump itself. The second location consists of the hose connections to the pump inlet and outlet. And finally, we have the spray gun connection to the high-pressure hose from where water could leak.
● Karcher Pressure Washer: Water Leaking from the Pump
If your Karcher pressure washer leaks directly from the pump, the fault lies in the piston seals that have worn out and need replacement.
Most pressure washer pumps use a positive displacement piston mechanism which pressurizes the water by pushing it across the tubing. The pistons have a seal that prevents water leakage from the pump. These seals tend to wear out after some time, which could result in a leakage. To check this, you may need to remove the pump’s housing and inspect the piston seals for wear and tear.
● Karcher Pressure Washer: Water Leaking from the Hose Connection
If your Karcher pressure washer leaks from the hose connections, the couplings at these connections have worn out and need to be replaced.
A coupling connects the hose to the pump’s low-pressure inlet at the pump. There’s a seal within this coupling that prevents a leak. If leakage occurs at this point, the coupling and its seal are damaged. Similarly, the outlet seal needs to be replaced if a leak occurs at the pump’s outlet connection to the high-pressure hose.
● Karcher Pressure Washer: Water Leaking from the Spray Gun
If your Karcher pressure washer leaks from the spray gun, check the hose-gun connection and press/screw it firmly. Check if the O-ring at the hose outlet is intact.
In most pressure washers, the high-pressure hose connects to the spray gun by a press fit. You should check if the fit is working correctly. If there are screws on it, make sure they are tight enough. If it still leaks, please check the O-ring at the hose and see if it lies there. A missing O-ring may have been causing this leakage.
You can buy all sorts of seals, gaskets, and O-rings for your pressure washer from multiple locations online or from your local dealer.
Karcher Pressure Washer: Water Pressure Problems
If you have trouble with the water pressure of your Karcher pressure washer, check out the troubleshooting guide below.
1. Karcher Pressure Washer: Low Pressure
To troubleshoot low water pressure, ensure adequate water supply and the inlet hose isn’t clogged with debris. Also, check if the nozzle is working correctly.
The water supply at the inlet must be sufficient for the pump to build the correct pressure. Make sure there are no kinks in the inlet hose. Also, most inlet hoses have a debris filter at the pump connection. Check that filter and dislodge any debris stuck in it. If the problem remains after this, ensure that you are using the correct nozzle and it isn’t plugged with any dirt.
2. Karcher Pressure Washer: No Pressure
If your Karcher pressure washer shows a loss of pressure, start by troubleshooting the water supply, the hose, and the nozzle. If that doesn’t help, check the unloader valve and the pump that could be malfunctioning.
While a loss of pressure may have been caused due to debris stuck or an inadequate water supply, in this case, the pump and the unloader valve can be at fault. Gradually adjust the unloader valve by keeping the pump on and the trigger pressed to see if it improves the pressure. If it doesn’t, try replacing the valve. You may also need to inspect your pump’s plungers and O-rings for any damage.
Over time, air bubbles due to cavitation can damage certain pump parts, exhibiting a loss of pressure. Most pumps sell as single units, so you need to take care of that before doing any replacement.
3. Karcher Pressure Washer: Surging Pressure
If your water pressure spikes, ensure your nozzle isn’t worn out. Also, it would help if you loosened the unloader valve to allow more water into the bypass and less into the spray gun.
The unloader valve of your pressure washer bypasses the high-pressure flow either to the pump inlet or the water tank. If your unloader is too tightly adjusted, it hardly bypasses any flow, so the pressure at the gun outlet is too high. Loosening the valve would allow bypass to occur and prevent pressure surges. If this doesn’t fix the issue, check your nozzle for signs of wear and replace it if it’s worn out.
4. Karcher Pressure Washer: Drops Pressure after a Few Seconds
If your water pressure drops after a few seconds, it may be due to a blockage in the nozzle or leaks in your hoses. An incorrectly adjusted unloader valve could also result in this problem.
Conversely to the above case of surging, if the unloader is too loosely set, it can cause a pressure drop at the gun. If the setting is too loose, even a small water pressure would be enough to overcome the spring tension and actuate the bypass. Hence, pressure at the gun exit reduces. Apart from this, inspecting your hose for any holes/leaks would be best. You should also check if your nozzle isn’t stuck with any debris.
5. Karcher Pressure Washer: Strange Noises from Pump
If a strange noise comes from your pump, it may be due to a faulty bearing or damaged connecting rods. Your pump may also give off noise if it isn’t lubricated properly.
Some more expensive models have a pressure washer pump with replaceable oil. More basic pressure washers use a wobble or axial piston pump where oil is added during manufacturing and then permanently sealed. For other models, you must check the oil regularly and change the oil when needed.
Depending on the model, your pressure washer pump needs to be lubricated every three months. Lack of lubrication causes sliding contacts between metal parts and produces noise. In that case, you can try to open your pump and check its bearings. A bearing replacement will probably eliminate the noise if lubricating the pump doesn’t solve the problem.
If you have a permanently sealed pressure washer pump with strange noises, you need to replace the whole pump.
6. Karcher Pressure Washer: Excessive Noise
If your pressure washer makes excessive noise, it can be due to damage to the pump’s internal components, mixing of air in the pump, a broken pump casing, or engine knocking due to bad fuel in the case of a gas model.
When the air gets trapped in a pump, it causes the plungers to produce a large grinding noise that can also cause damage to the seals and connecting rods. If the pump’s casing gets broken, it might result in vibrations that can cause additional noise.
Check the engine’s fuel quality if you have a Karcher gas pressure washer. I recommend always using ethanol-free, unleaded gasoline with a minimum octane number of 87 to reduce engine knocking.
7. Karcher Pressure Washer: Oil Leaking from the Pump
A pump that leaks oil most certainly has a damaged seal or a worn-out O-ring. If your pressure washer has a pump that is not permanently sealed, replace all the seals.
If you have a pump with replaceable oil and your pump warranty has expired, you should consider disassembling it. To replace the oil seals, I recommend buying an oil seal kit containing all sizes of seals and rings. While putting it back, ensure all bolts/fittings are tight enough. To prevent oil leaks in the future, avoid exposure to extreme conditions as it can damage rubber components quite easily.
If you have a pressure washer with a permanently sealed pump, there is no other option than to replace the whole pump.
8. Karcher Pressure Washer: Water in Oil
If water enters the pump oil, it is due to a faulty oil seal in the pump. If this is the case, replace the seal if the pump is not permanently sealed.
Water entering the pump oil makes it look milky. This can be a direct consequence of a faulty oil seal. Replacing the seal requires an entire pump disassembly, including removing the housing, valves, seals, and rings.
I recommend doing this only when the pump has run out of warranty. Under warranty, this should be repaired by the pump manufacturer. This only applies to pressure washers with a pump where you can replace the oil. Most budget pressure washers have a permanently sealed pump, this means that if the pump is damaged or broken, you can only replace it entirely.
9. Karcher Pressure Washer: Soap Not Dispensing from Reservoir
If your pressure washer is not siphoning soap from the reservoir, check if you’re using the right-sized nozzle or not. Also, you must inspect the soap injector kit and replace damaged or worn-out parts where needed.
For the soap injection function, the owner’s manual recommends a specific type of nozzle that provides suitable suction pressure for the detergent. Check that nozzle type and make sure you use that. If that doesn’t fix the issue, check your soap injection kit and ensure there aren’t any blockages in the nozzle. You can buy a chemical injector repair kit to find all the spare parts you need.
Troubleshooting table for a Karcher Pressure Washer
Problem | Cause | Solution |
The pressure washer is not producing high pressure | Hose with small diameter | Replace your hose with a 1″ (25mm) or 5/8″ (16mm) hose |
Restricted water supply to the washer | Check for the kinks and leaks in the hose | |
Inadequate water supply | Ensure the water source is unobstructed and fully turned on | |
Clogged intake filter | Remove the filter and rinse it with warm water | |
Air in the pump | Ensure that the hose and fittings are airtight. Shut off the washer and squeeze the trigger until water flows steadily from the spray tip | |
The suction tube or detergent bottle is not connected properly | Install the suction tube and detergent bottle correctly | |
Detergent too thick | Dilute the thick detergent by adding water | |
Obstructed spray tip | Remove the debris with a needle | |
No pressure tip on the wand | Install a suitable pressure tip at the end of the wand | |
If your model has a belt, it can be loose. | Tighten or replace the belt. |
Problem | Cause | Solution |
Pulsing pressure washer (output pressure varies high and low) | Inadequate water supply | Ensure that the water source is fully on and check the hose for kinks and blockage |
Obstructed spray tip | Remove the debris with a needle | |
Pump sucking air | Ensure that the hose and fittings are airtight. Shut off the washer and squeeze the trigger until water flows steadily from the spray tip | |
Clogged intake filter | Remove the filter and rinse it with warm water | |
Calcified hose, tip, or trigger | Clean the hose, pressure tip, or trigger with vinegar or a cleaner designed for this purpose |
Problem | Cause | Solution |
Noisy Pump | Air in the pump | Ensure that the hose and fittings are airtight. Shut off the washer and squeeze the trigger until water flows steadily from the spray tip |
Clogged inlet filter | Remove the filter and rinse it with warm water | |
Pump leaking water | Damaged or worn water seals | Replace the seals with new ones or call a professional |
Loose fittings | Ensure that all the fittings are tight | |
Erratic water pressure, changing up and down | Unloader valve | Check and clean the unloader valve. If in bad shape, replace it |
No output pressure. Or the motor stops when using the trigger (electric models) | Unloader valve | Check and clean the unloader valve. If in bad shape, replace it |
● Troubleshoot Karcher Electric Pressure Washer Motor issues:
Problem | Cause | Solution |
The motor won’t start | The power switch is in the “OFF” or “0” state | Turn the power switch “ON” or “1” |
Cord not plugged | Plugin the power cord | |
Damaged, too long, or improper extension cord | Replace the existing cord with a 25′ (7.6m) 14 AWG cord or a 50′ (15m) 12 AWG cord | |
Inadequate power from the electrical outlet | Plug the cord into a different outlet | |
The pressure washer circuit breaker tripped | Please wait for the washer to cool down and restart it | |
The motor buzzes but fails to run | Loss in voltage due to the extension cord | Plug the unit directly into the outlet without an extension cord. If the problem isn’t solved, replace the extension cord |
Low supply voltage | Ensure that only the pressure washer runs on that circuit at the time of use | |
Residual pressure in the system | Shut off the washer and squeeze the trigger to release pressure | |
Residual friction among the internal components | Cut the water supply and turn the machine ON for 2 to 3 seconds. Try it a couple of times or until the motor starts. Don’t let the machine run dry for more than 3 seconds. | |
Unit not used for long periods | I recommend calling a professional for help | |
Motor not working | Faulty Timer | Disconnect the leads from the timer. If your pressure washer doesn’t turn off after the time out, the timer is faulty, and you need to replace it. |
● Troubleshoot Karcher Gas Pressure Washer engine problems:
Problem | Cause | Solution |
Leaks in the spray wand, spray tip, or extension | Damaged or broken O-rings or plastic insert | Replace the worn O-rings or call a professional |
Pressure washer pump dripping oil | Worn or damaged oil seals | Inspect the oil seals and replace them if worn |
No water from the washer outlet | The water supply is off | Turn the water supply ON |
Kink in the hose or faucet not fully open | Remove any kinks and debris from the hose or water lines. Check and fully open the faucet. |
Problem | Cause | Solution |
The motor won’t start | Check the battery | Check if the battery is charged correctly. Charge or replace when in bad condition. Examine the battery terminals for a proper connection. Clean if needed. |
Check the fuel filter | Clean the fuel filter if dirty. In that case, check the gas tank, as this is the most likely culprit. | |
Check the gas supply | Check the fuel level and add if needed. Ensure that the gas can flow to the carburetor. Remove any blockage. | |
Check the Air-filter | Clean the air filter. Replace it when it is in bad condition or it is a paper air filter. | |
Check the carburetor | Remove and clean the carburetor with some carb cleaner. It is also possible to clean it without removing it. | |
Fuel gap blocked | Check that the hole in the fuel cap is open. Clean if needed. | |
The engine is stalling, or starts and stops | Check the carburetor | Remove and clean the carburetor with some carb cleaner. It is also possible to clean it without removing it. |
Air filter | Clean the air filter. Replace it when it is in bad condition or it is a paper air filter. | |
Check for bad gas | Suppose you have old gas, more than a few months old. It can turn bad. Drain and replace the gas. Next time add a fuel stabilizer. |
Will adjusting the unloader valve affect the overall performance of my pressure washer?
Adjusting the unloader valve can improve the performance of your pressure washer. It helps regulate the water flow and maintain optimal pressure levels for efficient cleaning.
Can I use any type of detergent in my pressure washer?
You should use only high-pressure washer detergent to avoid damage and ensure optimal performance for your Karcher pressure washer.
Very informative, I didn’t know there were so many things to check on a pressure washer
Thank you, Allen! Glad you found the information useful. Pressure washer maintenance is key to its longevity. Let me know if you need more details.
Helpful video links provided, thanks for the additional resources
Glad you found the video links useful! Let me know if you need more information on Karcher pressure washer troubleshooting.
This was helpful, I had no idea what to do when my pressure washer was leaking
Veronica, I’m glad the post helped you with your leaking pressure washer. Check the pump, hose, and spray gun connections for any issues and consider replacing seals or couplings if necessary.
Will using cold water instead of hot water affect the performance of my pressure washer?
Using cold water instead of hot water in your pressure washer won’t affect performance. Keep an eye on the pump and water delivery system for smooth operation.
Thanks for providing such detailed troubleshooting steps
Thank you for the feedback, Julie. I’m glad you found the troubleshooting steps helpful. Let me know if you have any other questions or need further assistance.
How can I prevent my pressure washer from getting clogged with debris?
Hi Carmen! To prevent your Karcher pressure washer from getting clogged, make sure to check the nozzles for blockages and adjust the unloader valve for optimal settings. Hope this helps!
I can’t wait to try these solutions on my pressure washer, thanks
Glad you found the solutions helpful! Be sure to check the connections and seals. Let me know if you need any more help. Happy cleaning!
I never knew about the unloader valve, thanks for explaining
Glad to have helped, Eli! Feel free to reach out if you have any more questions about pressure washer maintenance.
Very thorough explanations, it makes it easier to understand the problem
Thank you for your kind words, Cherly. I’m glad you found the explanations helpful for understanding pressure washer problems. Let me know if you have any other questions.
How long does a typical pressure washer pump last before needing a replacement?
Typically, a pressure washer pump can last between 500-800 hours before needing a replacement. Regular maintenance can help prolong its lifespan.
Can the detergent reservoir of a pressure washer be cleaned separately?
Yes, the detergent reservoir of a pressure washer can be cleaned separately. Check the blog post for detailed troubleshooting guides and the specific steps for cleaning the reservoir.
Good to know about the seals and O-rings, I’ll check mine
Thanks for checking your seals and O-rings, Don. It’s crucial for optimal pressure washer performance. Let me know if you need any help troubleshooting further!
What is the best way to clean the nozzle of a pressure washer?
To clean the nozzle of a pressure washer, make sure it’s free from any blockages before using. Try soaking it in vinegar to remove any dirt buildup.
Great guide, I’m going to try these tips on my pressure washer
Glad you found the guide helpful, Brandon! Good luck with troubleshooting your pressure washer. Let me know if you need any more assistance.
I appreciate the guidance on how to fix water pressure issues
Thank you, Ivan! I’m glad you found the guidance helpful to fix water pressure issues with Karcher pressure washers. Let me know if you have any more questions or need further assistance.
How often should I lubricate the pump of my pressure washer?
For optimal performance, lubricate your pressure washer pump every three months. Check seals and bearings regularly for wear and tear or noise issues to ensure smooth operation.
Is it normal for a pressure washer to vibrate a lot during use?
Yes, a bit of vibration is normal, but excessive vibrations may indicate an issue with the pump or hose connections. Double-check those for leaks or wear.