how to fix a pressure washer pump

How-To Installation Product & Troubleshooting Problems Pressure Power Washer and Pump Maintenance

March 24, 2021

HAVING PRESSURE WASHER PUMP ISSUES? START TROUBLESHOOTING HERE.

WRITTEN BY: KATE HUFFMAN

Having some issues with your pressure washer pump?

Check out our list of tips and tricks below to get your power washer back up and running. These troubleshooting tips are great for both newly installed pressure washer pumps as well as older ones that may be giving you problems.

Step 1: Verify Fitment

This might seem like a no-brainer, but you would be surprised how tricky it can be to make sure you're getting a replacement pump that's designed to work for your pressure washer. Shaft diameter and orientation are extremely important to check when purchasing or installing a replacement. Check our fitment chart at the link here to make sure your replacement pump is the correct one for your application.

Step 2: Check the Keyway

If you're not getting any pressure, it's possible your key might have been nudged out of place during installation. Without the key engaging the engine shaft, your pump won't function.

To check this, remove your pump. If your key wasn't in place while your engine was running, make sure you inspect the pump's shaft allowance for any signs of damage before reinstalling.

We usually recommend putting a small dent in one side of the key (do NOT use tape or any other glue or adhesive). This will cause it to be wedged in the engine shaft groove, and the key won't shimmy up the shaft when you slide the pump on.

Step 3: Check Your Spray Tip

Even veteran pressure washer users might not know that the pump isn't what gives you a powerful spray. The pump is just a device to force water through a size restriction (ie; the nozzle/spray tips). The amount of force and the narrowing of the restriction in turn creates a given amount of pressure. Because of this, spray tips can wear out quickly. Make sure you keep some spares on hand, and if your washer suddenly loses pressure, trying swapping out tips. Half of the time, this will solve your problem!

Step 4: Inspect for Leaks

Any leaks, obstructions, or damaged o-rings can severely impact the amount of pressure your pump can produce. Check your wand and pressure hose, starting from the spray tip and moving backward. Then check your garden hose and the connection to the water supply. Fix or replace any leaking hoses or o-rings and then apply thread sealant if needed at your connections.

A man bolting down a power pressure washer pump from The ROP Shop.

Step 5: Engine Horsepower

If your engine is bogging down or stalling, you can check to see if the pump you purchased is producing too much PSI for your engine to handle. We usually recommend you stick to the following formula when purchasing a replacement pump:

6.5 max HP = 3600 max PSI or less

6 max HP = 3100 max PSI or less

5.5 max HP = 2800 max PSI or less

5 max HP = 2600 max PSI or less

4.5 max HP = 2400 max PSI or less

If your replacement pump is over the max PSI recommendation for your power washer engine, you might be able to adjust the unloader valve down to a PSI rating that is better suited for you. Just follow the adjustment instructions below for "Too much pressur".

Step 6: Adjust Unloader Valve

Did you purchase one of our Himore brand pumps? If so, it came with an adjustable spring-style unloader valve. Usually, the pump comes pre-adjusted to the halfway point between the minimum and maximum pressure. If you need to change the pressure setting, follow the directions below.

Please note: All pressure adjustments require holding the HEX head bolt on the tip of the unloader valve while adjusting.

Not enough pressure? Tighten the silver 17mm adjustment nut ¼ turn. Tighten the gold 10mm nut to hold the adjustment nut in place. Check the pressure and repeat if necessary. You can complete two full turns in if needed, but not more.

Too much pressure? Loosen the gold 10mm nut. Loosen the silver 17mm adjustment nut ¼ turn. Tighten the gold 10mm nut to hold the silver 17mm adjustment nut in place. Check the pressure and repeat if necessary. You can complete two full turns out if needed, but not more.

RUGGED U: HOW TO INSTALL THE ROP SHOP PRESSURE WASHER PUMP - INSTALLATION TIPS AND TRICKS

Step 7: Check Water Temp

If your pump is overheating, there are a couple of possible causes. Do you have a hot and cold outdoor water faucet? If so, make sure you're using cold water only. Also, if your hose has been lying in the sun for a while, the water inside could be too hot for your pump. Before hooking your garden hose to your pump's water inlet, turn the faucet on and let the water flow until it's cool.

The second reason your pump could be overheating is that you're leaving it in bypass mode for too long. Your pump is auto-cooled by the water flowing through it. If there's no water flow, there's no cooling action. To correct this, squeeze your spray trigger and get the water flowing every sixty seconds.

If you've followed all the above steps and you're still not getting the pressure you were expecting, please contact The ROP Shop's customer service team by sending us an e-mail, chatting on our website, or giving us a phone call.

If you need help installing your new pump, check out this helpful video. You can also check out the Rugged U video on Troubleshooting issues with your pressure washer. We hope this helps and as always... Stay Rugged.

NEED HELP FINDING THE RIGHT REPLACEMENT PUMP FOR YOUR PRESSURE WASHER?

SEE OUR PUMP CHART TO VERIFY YOUR FITMENT

PUMP FITMENT CHART

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