How to Troubleshoot Pressure Washer Problems Like a Mechanic (Even if You Have Zero Experience)

Pressure Washer Troubleshooting Tips for BeginnersYou ever helped a neighbour fix something?

Be careful because once you do – and word gets around – you’ll be the go-to-fixit-guy-or-gal for everyone and everything.

Trust me, I know. All my neighbours now know me as the power equipment and pressure washer troubleshooting guy.

Here’s what happens when you’re the neighbourhood fixer: 

4 pm last Saturday I’m in the shed changing pressure washer oil, and over the fence my neighbour says:

“Hey, James, come fix my pressure washer and I’ll give you a beer.”

5 minutes later (beer in hand) he tells me he bought a used pressure washer with water pressure problems…

…It was an electric and started-up fine but when in-use pulsed out water to start, then after 10 seconds fell to low pressure.

My pressure washer troubleshooting experience told me it was air in the pump causing the problem. We switched off the electric motor but kept the water running through the pump. After holding the trigger to keep the water running through the machine we managed to clear the air from the pump and lines. My neighbour turned the machine on again and it worked. Full pressure, no pulsing.

Why you’ll love this beginner’s guide:

Nothing is worse than a pressure washer that starts up but won’t pressure wash properly. You get excited hearing it roar to speed but then it doesn’t properly clean your surface.

That’s why we put together this in-depth power washer troubleshooting guide for you… So you can fix the problem from your garage – even with zero experience and minimal tools.

Jump to each section:

Gas and Electric Pressure Washer Troubleshooting Tips for 20 of the Most Common Pressure Washer Problems

There are 20 pressure washer issues that are by far the most common.

Here’s how we know what they are:

  • Reading 300+ emails from pressure washer users asking for help to solve their machine’s issues and counting the occurrences of each fault in an Excel spreadsheet.
  • Going through 16 popular pressure washer brands’ Operating Manual and tabulating the troubleshooting sections’ listed problems and solutions.
  • Looking through my power washer logbooks over the last 8 years to see the most common issues.

After spending 14+ hours gathering the data the common faults could easily be broken down into 5 sections: Water pressure problems, water leaking issues, gas machine specific problems, electric pressure washer faults and other common problems. From there the troubleshooting tips are broken down to 3 columns: What’s wrong, most likely cause and how to fix.

Quick note:

  • Always check your Operator’s Manual for troubleshooting tips and safety first. Be aware many of the problems have 5 or more possible solutions for you to try.

Summary Table of Troubleshooting Tips:

The goal of this entire page is to make the most useful pressure washer troubleshooting guide on the internet. We constantly update and improve this table. It was last updated July 5, 2017.

Water Pressure Problems
What's Wrong?CauseHow to Fix
1. Low pressureInsufficient inlet water supplyUnkink garden hose, ensure full water pressure coming from tap, use large enough diameter garden hose (see manual)
Blocked inlet water filterRemove garden hose connection and remove debris
None or incorrect nozzleEnsure correct nozzle being used
2. No pressureDamaged unloader valveAdjust unloader screw, check for damaged seals/springs
Damaged pump inlet valves/manifoldDisassemble pump and replace/clean components of inlet manifold
3. Pulsing pressure (high then low)Damaged pump inlet valves/manifoldDisassemble pump and replace/clean components of inlet manifold
Faulty pumpReplace pump
Pump sucking airTurn off machine (but not water supply) and release pressure by squeezing trigger gun
Obstructed nozzle, water inlet filter or gun/spray wandUse needle to clear nozzle, fresh water to flush water inlet and vinegar to clear any deposits in gun/wand
4. Spiking pressurePoorly calibrated unloader valveAdjust unloader to proper pressure as per manual
5. Pressure drops after a few seconds useNozzle blockedClear nozzle with needle
Issues with unloader valveRemove unloader and clean/repair
6. Pressure washer isn't cleaning the surfaceUsing wrong nozzleSwitch to higher pressure spray nozzle
Water Leaking
What's Wrong?CauseHow to Fix
7. Water leaking from pumpSeals broken, cracked or wornReturn and replace under warranty
Loose bolts on pump assemblyTighten bolts to ensure pump casing properly sealed together
Thermal valve activatedWait 5 minutes before using (it will de-activate once cool enough)
8. Water leaking from garden hose connectionBroken or improper connectionConnect properly
Broken rubber washerReplace
9. Water leaking from spray wand or connectionsBroken o-ring inside hose connectionReplace o-ring or return hose for new
Not properly connectedConnect properly
Gas Power Washer Issues
What's Wrong?CauseHow to Fix
10. Engine will not startNo gasFill with gas
Choke is wrong positionMove to correct position as per manual
Pressure build upSqueeze trigger gun to release pressure in system
Spark plug wire not connectedConnect wire
Faulty spark plugReplace with new
11. Engine stops running while in useLow oil levelCheck and fill oil
Dirty air filterClean or replace it
12. Engine not providing enough powerDirty air filterClean or replace
Engine not running at correct RPMAdjust RPM to engine specs with pump detached
13. Oil dripping from engineWorn sealsReplace seals (covered by warranty)
14. Water in oil - looks milkyWorn or broken pistons allowing water throughRepair engine through warranty
Worn sealsReplace seals (covered by warranty)
Electric Pressure Washer Problems
What's Wrong?CauseHow to Fix
15. Machine won't startElectric outlet is faultyCheck main fuse, check plug
Not plugged inPlug in
Faulty motorReturn under warranty
16. Motor stops running while in useLow voltageCheck voltage is within motor specified range
Other Common Problems
What's Wrong?CauseHow to Fix
17. Chemical/detergent injector not workingUsing wrong nozzleInsert black soaping nozzle on wand
Soap tube inlet filter clogged (hose end that sits in soap bottle)Flush with fresh water
Soap inlet valve is clogged or blocked (pump side of tube)Remove hose and use small Allen key to push through hole to remove debris/unstick the ball valve
Detergent mixture is too thickAdd more water to dilute
18. Irregular bypass causing pressure fluctuations (sometimes) after useWorn or broken unloader valve seals, springs or other componentsRemove and replace
Unloader valve not properly installedRemove and install correctly, properly seating the valve at the bottom of the pump housing
Water leaking from unloader valveReplace worn or broken seals and re-install unloader valve to specification
Dirt in unloaderRemove and clean
19. Excessive noiseWater intake is blockedCheck and clean or replace
Not enough oil in engineCheck and add oil
Not enough oil in pumpDisassemble and check (if possible) and add oil, otherwise return under warranty
20. Oil leaking from pumpLoose bolts/fittingCheck and tighten
Damaged parts like seals or pistonsIf comfortable disassemble to check, clean and replace, otherwise return under warranty

Instructions How To Correct The Tricky Issues 

In this section are instructions how to fix the tricky pressure washer issues, namely the ones that require you to tear down the pump.

The Lazy Man’s Way to Diagnose Water Pressure (No Pressure) Issues

Here’s the 5 step approach to solving 95% of water pressure issues in 10 minutes or less:

  1. Check water supply: Open the water supply valve to full to ensure the pump is getting enough flow.
  2. Check hose for kinks: I can’t tell you how many times I’ve tested a pressure washer, got everything going, only to pull the trigger have it not reach pressure. I check the inlet for blocks. I check the nozzle. I check the water is on. And after all these things check out and it’s still not working I turn it off to read through the manual to find out what I’m doing wrong. Then, all of sudden, I notice a kink in the hose and realize how much an idiot I was not to notice. I fix the kink start the machine and it all works fine. Don’t make this mistake – always check for kinks.
  3. Release air from system: Always connect the garden hose to the power washer first. Then turn the water tap on and pull the trigger gun to release water from the system at the garden hose water pressure before starting the engine or motor. This will release all the pressure from the system and allow the pump to function.
  4. Ensure correct nozzle and nozzle not clogged:
    Clearing Pressure Washer Nozzle Blocks With Needle

    How to Clear the Nozzle Tip

    Use a needle to clear the nozzle tip of any debris. Any blocks at the nozzle will cause decreased flow and increased pressure in the systems, possibly triggering the unloader to enter bypass.

  5. Still experiencing water pressure problems? Okay, no worries, we’ll need to get the tools out to remove unloader valve and check for issues – see below.

Everything You Need to Know About Removing the Unloader Valve to Check for Issues

Unloader valves allow water to run through the pump when you are not holding down the trigger on the pressure gun. If there was no unloader valve then pressure would build inside the system (when not in use) so when you did pull the trigger it would stall the engine or explode a weak link part – probably the pressure hose o-ring.

Check out where the unloader is located on 3 different pressure washer pumps:

Pressure Washer Unloader Valve Locations Examples

As you can see the unloader is located on the exit side of the pump because it allows the pressurized water to flow back through the pump when it isn’t exiting into the high pressure hose (you’re not pressure washing anything).

Take a look at two different disassembled unloader valve assemblies:

Disassembled Unloader Valve ExamplesThe one on the left is from the Stanley gas pressure washer also shown in the above image on the left. It is a flow actuated unloader.

The unloader on the right is from an AR Blue Clean electric pressure washer. It is a pressure actuated unloader.

Both these assemblies can be taken out of the pump for cleaning and repair, without damaging them.

The Difference Between Flow and Pressure Actuated Unloaders

  • Flow actuated – As the name suggests, these unloader valves respond to water flow stoppage. When there is no flow leaving the nozzle the valve will “open” allowing water to flow back to the pump inlet.
    • Pros: Safer because doesn’t require pressure build up.
    • Cons: More sensitive to system issues like a clogged nozzle, incorrect nozzle orifice size and other flow problems.
  • Pressure actuated – Instead of responding to flow, this type of unloader is forced open by an increase in water pressure allowing water to bypass back to pump inlet (this pressure is increase is usually caused by flow stoppage).
    • Pros: Less sensitive to flow issues within the system because it responds only to trapped pressure on the outlet side of the pump.
    • Cons: Less safe because it needs pressure rise to work (could cause failures within system).

Troubleshooting the Unloader Valve

Many pressure problems begin and end at the unloader. A cracked o-ring, dirt caught in the spring or a stuck shaft are the most common issues solved by simply removing the unloader and cleaning/looking for issues.

12 Essential Tools and Accessories 

The 12 below tools are the most commonly used to repair pressure washers.

Pressure Washer Essential Troubleshooting Tools

Tools

Using the below tools I’ve fully disassembled (all the way down to removing the gas engine piston seals and crankshaft) and put back together: 3 electric pressure washers and 4 gas power washers. Let’s run through the tools, where they are used and if you should buy a complete tool kit or individual tools (and from what tool brands) for repairing your pressure cleaner.

Hex/Allen Keys

Allen keys Used on Pressure Washer

Use hex key to remove pump

These are one of the most used tools troubleshooting pressure cleaners because most pump assemblies are fastened together with hex head screws. They are often called Allen head after the company Allen Manufacturing that started mass producing hex screws and hex wrenches (Allen wrenches/keys) to fasten them in the early 1900s.

There are 3 main advantages to hex head screws:

  1. Recessed head to make screw durable and unlikely to damage.
  2. Use same hex head on different screw types, sizes and threads (thus only one hex key tool required). These would require several different wrenches if they didn’t have hex head. This is likely the reason behind their common use on bicycles – one hex key pocket-size set can help you disassemble and repair your entire bike (many different screw sizes and types but if they all have hex head you only need your hex keys).
  3. Torque wrench can be used to tighten them to exact design specification.

Needle-nose Pliers 

Needlenose Pliers Often Used To Troubleshoot Pressure Cleaners

Use needle-nose pliers to remove the spark plug wire cover

Needle-nose pliers are very handy because they reach small areas to remove o-rings, seals and valves. I use them often when tearing down a pump to fix water pressure issues. I also use them when putting it back together to seat valves and get o-rings and seals into position.

You’ll be very happy to have a set lying around when trying to sort out your power washer faults.

I had a hard time deciding to put hex keys or needle-nose pliers first because they are both used often.

Screwdrivers

Screwdrivers are very useful for troubleshooting electric pressure cleaners

Use screwdriver to get inside electric machines

Almost the only tool you need to disassemble electric pressure washers is a screwdriver.

Electric machines’ plastic covers – which hide the pump and motor – are held together with Philips head screws.

Gas machines also use Philips – often to clamp down wires and assemble their frames etc.

In addition, you’ll want some slotted screwdrivers to help wedge/drive out certain parts like pump plunger seals. Torx head screws are also used once you get to the engine block.

Sockets & Ratchet

Sockets needed to remove pump head on pressure washers

Use ratchet + sockets to remove pump head

Every tool set needs sockets & ratchet and wrenches despite them doing the same thing.

Why?

Because you can have one ratchet and socket heads for every bolt size in a compact case. The ratchet allows you to remove or tighten bolts without repositioning and deep socket attachments allow reach to tight spots.

However, you also need wrenches, especially the open-end side to get to bolts from the side when the top isn’t in reach.

Wrenches

Wrenches required on pressure washers to get to tight spaces

Use a wrench for screws in tight spots

Wrenches have been in use since the 15th century and are probably the most well-known and owned hand tool.

Many prefer to use a ratchet-socket combination because it is quick (don’t have to reposition tool when tightening or loosening fastener) and it’s easier to store (and carry around) 50+ socket heads instead of 50+ wrenches.

But: When you need to get to screws in tight spots you need a wrench. And pressure washers have some tight spots.

Rubber Mallet or Hammer

Hammer or Rubber Mallet is Used to Troubleshoot pressure washers

Use a hammer to free stubborn parts

Did you know hammers are the oldest known hand tool?

Yup, hammers with handle attached to hard impacting head have been discovered and dated back 30,000 years. And nearly exact replicas of the modern hammer have been found and dated to around 5,000 BC.

They have been useful to humans for 1000s of years – a pretty cool tool.

While troubleshooting pressure cleaners they are used to free stubborn parts like the pump head valve plate.

Utility Knife

Utility Knife Helps To Remove Detergent Tube From Pressure Washer

Use a knife to cut soap tube

Cutting tools like knives have been in use nearly as long as hammers.

They are great help to troubleshoot faults because they make quick work removing the detergent hose and help wedge under tight fitting components to loosen them. Cutting the soap hose is fine because there’s lots of it and you’ll probably damage it using pliers or other means, anyways.

In addition, you probably own several knives already so no need to go out buying any just to help solve pressure washer issues.

Snips

Snips help troubleshoot pressure washer problems

Use snips instead of knife when needed

I like using snips instead of a knife because it’s more precise and quicker.

My snips are sheet-metal snips and cut through tree branches, hoses, and thick plastic or rubber without issue. So if you burst a pressure washer hose, you could cut it shorter (with snips) and install the fitting instead of buying brand new. We did this all the time at a job I had as a 19 year old using a pressure washer to clean a factory parking lot and truck scale every-single-morning.

Snips are a must-own.

Accessories

There’s no need to go into detail about these accessories. You will 100% want to have silicone grease when you reinstall o-rings, and WD-40, thread tape and grease cleaner will be useful, no doubt.

What’s the Best Tool Set to Get?

Best Pressure Washer Troubleshooting Tool Set

Click image to see current price on Amazon for this 170-piece Crescent brand tool set

The single kit that has everything you need to troubleshoot pressure cleaners (except for a rubber mallet) is this 170-piece mechanics tool set by Crescent.

You can see that it has:

  • Hex keys
  • Pliers
  • Ratchet + sockets,
  • Screwdrivers
  • Wrenches
  • Snips built in to the needle-nose pliers, and
  • Carry case.

If you don’t already own all these hand tools – and you plan on fixing your power washer on your own – then this is the best tool kit.

See full specs on Amazon here…

Troubleshooting Hot Water Power Washers

Hot water pressure washers can suffer 3 faults:

  • No hot water produced
  • Too much/weird color smoke out the burner
  • No flame from blower.

There’s 15 or so reasons why you may experience these faults and the same number of fixes.

Before we get into the fixes, let’s learn more about the burner components.

How a Pressure Washer Burner Works

A hot water pressure washer has a burner to heat the water. The burner uses diesel or kerosene & air + electricity to generate a fire inside a chamber with water circulating around the exterior in tubes coiled like a snake. Water enters at the bottom and by the time it reaches the top – having circulated through all the coil around the flame – exits at the top as hot water.

The burner adds risk/danger to troubleshooting because of the, well, fire. We recommend you take it to a pressure washer repair centre to get fixed. However, there are some simple fixes.

Pressure Washer Burner Anatomy

Anatomy of a hot water pressure washer burner unit

What parts does a pressure washer burner have?

  1. Steel tubing/coil
  2. Insulation
  3. Fuel pump/motor and fuel spray nozzle
  4. Blower motor
  5. Electrodes/ignition tranformer
  6. Thermostat/controller
  7. Flow switch
  8. Pressure release valve
  9. Air adjustment slider
  10. Fuel filter
  11. Exhaust

Here’s a 9-minute video to explain everything on burner troubleshooting:

Brand Specific Tips & Tricks for Diagnosing and Fixing Power Washer Issues 

Let’s look at popular brands, the types/styles of pressure washer they make (including pump brand & type), common issues with those pumps and where you can find further troubleshooting information.

Troy Bilt Troubleshooting Resources

Troy Bilt sells home-use medium-duty gas powered machines with AR Blue Clean axial cam pumps.

Briggs & Stratton is Troy Bilt’s OEM (original equipment manufacturer) meaning Troy Bilt specifies certain things about the machine (eg. Honda or Briggs engine) and Briggs makes them in their factories. The Troy Bilt sticker is then placed on the power washer for sale.

A common fault is that your Troy Bilt will experience no pressure or low water pressure when you start washing. This is often caused by a dirty or broken unloader valve assembly (see above tips).

Further information: Troy Bilt Support Center

Generac

Generac makes and sells residential-use medium and heavy-duty machines as well as belt driven units for commercial use. They have an OEM overseas to manufacture their pumps and engines then assemble them back in their factories in the USA.

Further information: Generac Pressure Washer Support Product Lookup

Karcher

Karcher makes all types/styles of pressure washers through their own brand and subsidiary brands including Hotsy, Shark and Landa. They are easily the biggest pressure washer maker and seller in the world. They makes models with all types of the best small engines and pumps and have an extensive rental and service network through their subsidiary brands.

Further information: Karcher Pressure Cleaner Knowledgebase

Simpson

Simpson Cleaning sells home and commercial use machines with Kohler, Honda and Simpson OHV engines. The pump brands they use are two in-house brands: OEM Technologies (axial cam) and AAA Pumps (triplex). They also use CAT Pumps brand on some of their premium residential and commercial machines.

Simpson Cleaning are some of the most popular residential gas machines because they offer great value for money and their pressure washers’ wheelbarrow stance is sturdy and much easier to move around compared to the common upright designs.

Common problems include low or no pressure after a few seconds use and soap not entering system properly.

Further information: Simpson Support Page

Now What?

If you pressure wash you’re bound to need to troubleshoot an issue at some stage. Whether it be no water pressure because of a hose kink or low pressure because of a busted o-ring inside the unloader…

…it will happen eventually – but since you made it this far you will have the knowledge to sort your problem out from your garage – with minimal tools and time.

To decrease the risk of having major issues, take a look at the 7 best for home use – these are the best designed and least likely to fail.

Okay, to wrap up: Let’s review the gist of the tips outlined in this guide:

  • Water pressure issues (no, low and/or sporadic water pressures): Check water supply is on full and no hose kinks. Check inlet filter isn’t clogged. Check nozzle isn’t blocked. Turn off engine/motor (but keep water on) and pull trigger to release air from system. If none of this works, it may be the unload valve being stuck due to dirt or broken parts. See unloader section above.
  • Water leaking from connections: First ensure connections are securely fitted. If water is squirting out while pressure washing it is most likely a busted o-ring inside the the pressure hose. Contact support and get them to send new o-ring or hose.

Be sure to review the summary table above and double the check the brand specific support pages before giving up and returning the machine.

Sources

  1. Troubleshooting Pressure Washer and Power Washer Problems.” www.PressureWasherTroubleShooter.com
  2. Hammer History.” Wikipedia.org
  3. All About Unloader Valves.” www.ePowerWash.com