If your pressure washer isn’t working correctly, this troubleshooting guide will walk you through how to get it working again. We’ll show you all the possible causes of common problems and how to fix them, including problems with starting, low pressure, leaking and more.
Contents
Troubleshooting problems with starting
If your pressure washer won’t start or won’t stay running, there are 21 possible causes. Most are related to incorrect setup (like your fuel valve isn’t all the way open), but it depends whether it’s gas-powered or electric-powered.
Won’t start
1. There’s no fuel.
Add the appropriate amount of fuel.
2. There’s no oil.
Add the appropriate amount of oil.
3. The power switch is off.
Turn the engine’s power switch on.
4. The fuel valve is closed.
Open the engine’s fuel valve.
5. The choke is closed.
Open the engine’s choke.
6. The spark plug is fouled.
Check the condition of the plug. Clean it if you can, otherwise replace it with a new one.
7. The spark plug wire isn’t connected.
Make sure the wire has a clean and secure connection (there may be dirt preventing contact).
8. The carburetor is clogged.
Check the condition of the carb. Clean it if you can, otherwise replace it with a new one.
9. The battery is dead. (electric-start systems)
Charge the battery (and make sure the cables have a clean and secure connection).
10. The cord isn’t plugged in.
Plug the power cord into a working outlet.
11. The power switch is off.
Turn the unit’s power switch on.
12. The outlet has no power.
Restore power to the outlet (there are several reasons it could be off), or just use a different one.
13. The GFCI tripped.
Press the reset button on the GFCI. If it won’t reset, see reasons here.
14. The thermal overload tripped.
Wait a few minutes for the motor to cool down, then press the overload reset button.
15. The circuit isn’t powerful enough (low amperage).
Make sure the circuit has enough amperage for the requirements of the motor.
Won’t stay running
16. There’s not enough fuel.
Add the appropriate amount of fuel.
17. The fuel is bad.
Drain the tank and add new fuel.
18. The air filter is dirty.
Check the condition of the filter. Clean it if you can, otherwise replace it with a new one.
19. The idle isn’t set correctly.
Adjust the idle to the recommended settings in the operating manual.
20. The circuit isn’t powerful enough (low voltage).
Make sure the circuit has enough voltage for the requirements of the motor.
21. The motor has an automatic start-stop.
Check if the motor has an automatic start-stop feature. If it does, it’s normal for it to stop during use.
Troubleshooting problems with pressure
If your pressure washer won’t build full pressure, there are 13 possible causes. Most are related to poor water flow (like the nozzle has some dirt stuck inside), but it depends whether there’s no pressure at all, or it’s pulsing (high then low).
No or low pressure
1. The water supply isn’t sufficient.
Make sure the garden hose has enough water pressure and flow for the requirements of the pump.
2. The water inlet is blocked.
Check the inlet filter for dirt or damage. Clean it if you can, otherwise replace it with a new one.
3. Something else is blocked.
One by one, check the high pressure hose, spray gun and nozzle for blockage. Clean accordingly.
4. The wrong nozzle is connected.
Connect a higher pressure nozzle (from low to high: black, white, green, yellow, red).
5. The unloader valve isn’t set correctly.
Adjust the valve to build more pressure (the exact method varies by model, but usually it’s a knob).
6. The unloader valve isn’t working.
See reasons here.
7. The engine or motor is underpowered.
Adjust the power if you can, otherwise contact the manufacturer.
8. The pump is damaged.
Repair the pump if you can, otherwise contact the manufacturer.
9. Something is leaking water or pressure.
Check for obvious leaking from the pump or any of the accessories and fix it if you can.
Pulsing pressure
10. There’s air in the system.
Hold the trigger on the spray gun until the water flow is consistent.
11. The unloader valve isn’t working.
See reasons here.
12. The pump is damaged.
Repair the pump if you can, otherwise contact the manufacturer.
13. The engine or motor is fluctuating.
Adjust the power if you can, otherwise contact the manufacturer.
Troubleshooting problems with leaking
If your pressure washer is leaking, there are 7 possible causes. Most are related to loose setup (like the hose connection isn’t completely tight), but it depends where the leak is coming from and whether it’s leaking water, oil or gas.
Leaking water
1. A connection is loose.
Tighten the connection where it’s leaking from.
2. A seal is damaged.
Replace the seal where it’s leaking from.
3. The unloader or thermal valve is working.
It’s normal for water to leak from these valves.
Leaking oil
4. A connection is loose.
Tighten the connection where it’s leaking from.
5. A seal is damaged.
Replace the seal where it’s leaking from.
Leaking gas
6. The fuel line is loose.
Tighten the clamp where it’s leaking from.
7. The carburetor is clogged.
Check the condition of the carb. Clean it if you can, otherwise replace it with a new one.
Troubleshooting other problems
There’s a few other common pressure washer problems besides the ones listed above, but they don’t fit into larger categories so we’ve listed them below in no particular order. Some are general issues, others are specific to gas or electric models.
Soap dispenser doesn’t work
1. The wrong nozzle is connected.
Connect the soap nozzle (usually black).
2. There’s not enough soap.
Make sure the end of the siphon is fully immersed in the solution.
3. The soap is too thick.
Add more water to dilute the solution, or use a different soap.
4. The siphon is blocked.
Check the siphon and filter for dirt or damage. Clean it if you can, otherwise replace it with a new one.
No water flow
1. The water supply is off.
Turn the water supply on.
2. The water inlet is blocked.
Check the inlet filter for dirt or damage. Clean it if you can, otherwise replace it with a new one.
3. Something else is blocked.
One by one, check the high pressure hose, spray gun and nozzle for blockage. Clean accordingly.
4. The pump is damaged.
Repair the pump if you can, otherwise contact the manufacturer.
Unloader valve not working
1. It’s not set correctly.
Adjust the valve to the recommended settings in the operating manual.
2. The seal is damaged.
Replace the seal with a new one.
3. The internals are dirty.
Check the condition of the internals. Clean them if you can, otherwise replace them.
Pull cord hard or stuck
1. There’s too much pressure in the system.
Hold the trigger on the spray gun to release internal pressure.
2. The engine is flooded.
Remove the spark plug, pull the starter a few times to clear it, then reinstall the plug.
GFCI won’t reset
1. The power cord is damaged.
Replace the power cord with a new one.
2. There’s a fault in the circuit.
Check for faults in the circuit (it may be a tripped breaker, outlet, etc.). Consult an electrician.
3. The GFCI is defective.
Replace the power cord with a new one.
Burner not working
1. There’s no fuel.
Add the appropriate amount of fuel.
2. The burner switch is off.
Turn the burner switch on.
3. The thermostat is set too low.
Adjust the thermostat to a higher temperature.
4. The spray gun is off.
Pull the trigger on the spray gun to ignite.
Pressure washer parts diagram
If you’ve never worked on a pressure washer before, it’s helpful to understand how it works before you start troubleshooting. Review the parts diagram below to learn the basics, but keep in mind, the exact breakdown of any pressure washer will vary between models.
- Starter cord
- Power switch
- Fuel valve
- Choke
- Fuel tank
- Fuel fill
- Oil fill
- Muffler
- Pump
- Water inlet
- Spray gun
- Spray gun trigger
- Hand grip
- Wand
- High pressure hose
- Accessory dashboard
- Detergent tank
- Handle
Additional troubleshooting resources
Some brands have additional resources that can help with troubleshooting pressure washer problems, like repair videos and parts finders. See the links below for available resources from each brand (plus phone numbers if you need to contact them for any reason).
- Ryobi: Product support | Replacement parts | Service centers | 1-800-525-2579
- Karcher: Product support | Replacement parts | Service centers | 1-800-537-4129
- Simpson: Service centers | 1-877-362-4271 (gas) or 1-800-381-0999 (electric)
- Sun Joe: Product support | 1-866-766-9563
- Greenworks: Replacement parts | Service centers | 1-888-909-6757
- DeWalt: Product support | Replacement parts | Service centers | 1-800-433-9258
- Generac: Product support | Replacement parts | Service centers | 1-888-436-3722
- Briggs & Stratton: Product support | Replacement parts | Service centers | 1-800-743-4115
- Honda: Product support | Replacement parts | Service centers | 1-770-497-6400