residential pressure washer

How To Troubleshoot 12 Pressure Washer Problems Like A Mechanic; The Complete Manual

What do you do when your pressure washer starts up but won’t pressure wash properly?

Someone created that thread in one of my favorite subreddits, the other day. And that has inspired this complete guide on how to troubleshoot pressure washer problems like a mechanic.

Now listen up:

Though this guide covers 12 electric pressure washer problem fixes. And for gas pressure washers as well.

It is always best to check your user’s manual first for the troubleshooting specified and explained by your manufacturer. By so doing, you avoid a lot of risks.

With that said:

Let’s start with an overview of the…

12 Common Pressure Washer Problems

  1. Pressure drops every time after a little use
  2. Pressure pulsing high and low
  3. Spiking pressure
  4. No pressure at all
  5. Low pressure
  6. Water leaking from connections or spray gun
  7. Too much noise
  8. Engine not starting
  9. Water leaking through the garden hose connections
  10. Water leaking through the pump
  11. Engine dripping oil
  12. Engine not providing enough power


You’re dead right:

But before we run over to the solutions, below are the…

12 Must-have Tools And Accessories For All Pressure Washer Owners

Now take this first:

The best thing is to invest in a complete tools set. And I always recommend the general-purpose kit of 170pcs tools & accessories from Crescent store. Look it up on Amazon.

But if you can’t afford one, build your mini toolbox with these 12 essential tools:

  1. Sockets and ratchet- to loosen or tighten bolts without repositioning in both open and tight spots
  2. Hex/Allen keys- for disassembling and assembling the pump
  3. Screwdrivers (Torx head, Philips head, and slotted)- to uncover the pump and motor of electric machines. Or to clamp down and assemble the wireframes of gas machines.
  4. Needle nose pliers- you need them when tearing down pumps to fix water power issues. Especially to remove valves, o-rings, and seals. And for putting the thing back together.
  5. Wrenches- for getting to the screws in extremely tight spots
  6. Utility knife- for cutting the soap hose when you need to. Also for wedging under tight-fitting components
  7. Hammer or rubber mallet- for freeing pump head valve plates and other stubborn components
  8. Snips- to cut a pressure hose shorter when it bursts instead of buying a new hose
  9. Thread tape
  10. Silicone grease
  11. WD-40
  12. Silicone grease cleaner

So, let’s head straight to the lazy man’s fixes to all the previously listed pressure washer problems below.

Starting with…

Troubleshooting Problem 1; Pressure Drops Every time After A Little Use

Always remember this:

Whenever you notice the pressure dropping after a little use, there are 2 possible problems attached. One is, you have a clogged nozzle. And the other is, there’s an issue with the unloader valve.

For A Clogged Nozzle

Know this first:

Each time there are clogs in the nozzle, the water flow will be decreased and pressure increased. Often, this forces the unloader valve to enter bypass.

To solve this in 3 steps:

  • STEP 1; grab a needle
  • STEP 2; push it through the nozzle hole
  • STEP 3; pull in, out, and sideways to remove debris

For The Unloader Valve Troubleshooting

All you need to do is wash it like this:

  • STEP 1; let your manual guide you to where the unloader valve is (the location varies between brands)
  • STEP 2; disassemble the unloader valve
  • STEP 3; wash with a brush in a washing solution
  • STEP 4; dampen with a dry towel and assemble

Moving on to…

Troubleshooting Problem 2; No Pressure At All

Now, this is more serious:

It’s either the unloader valve is damaged completely or the pump inlet/manifold is damaged beyond repair.

And the best solution? Replace those components altogether. Problem solved. Note: always purchase the replacement parts recommended by your manufacturer.

Next up:

Troubleshooting Problem 3; Spiking Pressure

Quick question:

Ever witness your system overdoing the water-shooting thingy? It can be a disaster. And is always caused by a poorly calibrated unloader valve.

But the solution is simple:

  • STEP 1; check the recommended pressure in the manual
  • STEP 2; adjust the unloader valve to this pressure level


So, how about…

Troubleshooting Problem 4; Pressure Pulsing High And Low

Riddle me this:

What does it mean when the pressure pulses high and then low, now and then? Don’t sweat it. The answer is either of these 4.

  1. You have a faulty pump; replace it
  2. Water inlet filter or gun/spray wand or nozzle is clogged; unclog and dry
  3. Damaged pump inlet/manifold; replace it
  4. Pump sucking air; just turn off the system and keep the water supply running as you squeeze the trigger gun to release pressure

Moving on…

Troubleshooting Problem 5; Low Pressure

I know the feeling:

It’s so annoying. Especially when you need a quick wash but you’ve got little drips instead of powerful waterjets.

Here are the likely causes of this:

  1. Incorrect nozzle or no nozzle at all
  2. Low inlet water supply
  3. Clogged inlet water filter

Now, the way out:

For Incorrect/No Nozzle At All

  • STEP 1; check your manual or reach out to your manufacturer to know the nozzle recommended
  • STEP 2; replace the incorrect nozzle

Follow the step-by-step explanation in the video below to replace your pressure washer turbo nozzle.

For Low Inlet Water Supply

  • STEP 1; gently unkink the garden hose
  • STEP 2; adjust the water pressure from the tap to maximum

You might as well change your garden hose to a bigger size. Or watch the powerful video below on how to improve water flow into a power washer pump.

For Clogged Inlet Water Filter

I have explained how to unclog a blocked inlet water filter previously. But I recommend this video on how to do washing machine water inlet filter cleaning.

Heading over to…

Troubleshooting Problem 6; Water Leaking From Connections Or Spray Gun

Here are the chances:

It’s either these two parts are not well connected or the o-ring inside the hose connection is broken.

But neither is a big mess:

For A Poor Spray Gun-To-Hose Connection

It is an issue that’s likely to occur after replacing your gun incorrectly. All you have to do is connect them properly, following the instructions in your manual.

Or do this instead:

  • STEP 1; disassemble the two parts
  • STEP 2; check the water flow level from the spigot. And make sure it’s set to the level recommended by the maker. (It’s usually between 2-3gallons per minute)
  • STEP 3; attach a splitter/split valve. This is to avoid having to disconnect the spray gun from the hose every day
  • STEP 4; skip step 3 if you’d rather be disconnecting them every day
  • STEP 5; attach a quick-connect fitting for quick and easy unplugging after use
  • STEP 6; finally connect the leader hose to the gun

This video below illustrates it better though:

For A Broken O-ring

Too much pressure from the spigot can break the o-ring inside the hose connection. And the best fix to this is an o-ring replacement.

To do this:

Follow the guide in the following video.

Next one:

Troubleshooting Problem 7; Too Much Noise

So, here’s the thing:

Whenever your system starts making excess noise, there are 3 likely causes linkable to this.

  1. There’s not enough oil in the pump
  2. The engine has run out of oil or has little oil
  3. The water intake is blocked

Let’s treat the issues separately:

For When There’s Not Enough Oil In The Pump

First question:

How much oil goes in a pressure washer pump? Quick answer; it depends on what figure your manufacturer suggests.

But in most cases, a bottle of 30W non-detergent oil is ideal for a full oil change.

To add oil to the pump, do this:

  • STEP 1; clear the pump for 2-3 minutes. Do this by switching off the water supply and detaching the spray gun from the wand.

Finally, switch on the engine and keep pressing the spray gun throughout the 2-3 minutes period.

  • STEP 2; remove the pump oil cap with a wrench and drain the existing oil
  • STEP 3; pour in a fresh oil and cap

For When Engine Runs Out Of Oil

Spoilers warning:

Just follow the same procedure for adding oil to the pump. But, please, use the engine oil recommended by your brand. See the next video for a complete guide on how to do it.

For When Water Intake Is Blocked

You def have a clogged water inlet. And I have explained how to unclog this previously in problem 5. But here’s a clear video to guide you on how to clear the blocked water inlet.

Moving on to…

Troubleshooting Problem 8; Engine Not Starting

Troubling but not overly complicated:

If your engine won’t start on when you try activating it, here are the causes and how to treat them;

  1. The spark plug wire is not connected – connect it properly
  2. There’s pressure building up somewhere – to release pressure from the machine, squeeze the trigger
  3. The choke is not positioned right – let your manual guide you to position it correctly
  4. You’re out of gas- refill
  5. The spark has faulted-out – replace with a new one

Note; if it still won’t start after doing all this, call a technician.

To the next one:

Troubleshooting Problem 9; Water Leaking Through The Garden Hose Connection

Not a big deal:

Though, at times, this only means that the hose/rubber washer is broken and needs replacement. But more than likely, all you have to do is connect the hose properly if it’s out of position.

Let’s move on:

Troubleshooting Problem 10; Water Leaking Through The Pump

A Big issue you have here:

The worst-case scenario is that the pump seals are cracked, broken, or worn. In this direction, you will need to cycle back to your manufacturer for a replacement or refund.


It might be that the thermal valve is activated due to overheating. If that’s the issue, wait for about 5-10 minutes for it to cool before using. You’ll be good.

Another possible cause:

It’s likely you have some loose bolts on the pump assembly. And all you have to do is tighten them. Check your manual on how to do this.

Next one:

Troubleshooting Problem 11; Engine Dripping Oil

Quick one:

Over time, oil will start dripping from the engine due to worn/broken seals. In fact, most manufacturers tell you when it’s likely to happen. In this case, you’re covered in the warranty.


Cycle back to your manufacturer for seal replacement.

Next up:

Troubleshooting Problem 12; Engine Not Providing Enough Power

Why does this happen?

Well, there are 2 things involved. The first possible cause is that you have a dirty air filter. And the second being that your engine isn’t running at the appropriate RPM (rotations per minute).

For When Your Air Filter Is Dirty

Just clean it. And here’s how to;

  • STEP 1; detach the air filter cover
  • STEP 2; pull out the air filter foam
  • STEP 3; wash with paint thinner or mineral spirit
  • STEP 4; squeeze out the liquid without tearing or twisting the foam

You can follow the explanation in the following pressure washer air filter cleaning video.

For When The Engine Isn’t Running At The Appropriate RPM

Now, this is straight-forward:

All you have to do is adjust the RPM to the one specified for the engine by the maker. Check your user’s manual to know the right RPM for your machine.

And that’s just about it.

Wrapping this up:


And there you have it:

The complete guide for how to troubleshoot pressure washer problems like a professional mechanic. I suggest bookmarking this page for easy reach when you need to fix a pressure washer issue.


If you have any questions, contributions, or thoughts to share, feel free to use the comment box. You may also let me know if I missed specific troubleshooting and I will add it to the post.

Author: Ibrahim Clouds

Hey! Ibrahim Clouds here. I am a weekend DIYer seriously crazy about home appliance projects/repairs and your go-to guy for great tips/nuggets/answers to all home appliance-related topics. And my job? Other than helping you here on Housechime, I also write Amazon listing copies (largely for home appliance sellers), and work as a ghost PR officer for some SMBs.

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