How To Choose The Correct Replacement Pump

If your pressure washer is running but fails to build up water pressure, don’t lose hope just yet; it’s possible that the pump is malfunctioning.

For most gas engine pressure washers, replacing the pressure pump may offer a more cost-effective solution than replacing the entire pressure washer. Fortunately, the process of replacing a pump is simpler than one might think. High-end pressure washers usually feature triplex or belt drive pumps, while entry-level gas pressure washers are typically equipped with Vertical Axial Pumps.

Unfortunately, most entry-level electric pressure washers are equipped with non-replaceable pumps. In such cases, it is often more practical to purchase a new unit altogether. Though, depending on your pressure washer model and your symptoms, there may still be parts available. If you have an electric pressure washer and feel like you may be having pump troubles, our service technicians are here to help! Simply start a chat, send in our contact form, or give us a call.

Identifying Your Pump Type

To ensure compatibility with your current machine, it is crucial to determine whether your pressure washer pump is axial or triplex.

Axial Cam Pump:

Examine how the pump connects to the motor. If the driveshaft of the motor aligns directly with the brass valves, it is an axial cam pump. In this design, the driveshaft directly spins the cylinders responsible for pressurizing the water.

Triplex Plunger Pump:

Check if the driveshaft runs parallel to the brass valves. A parallel configuration indicates a triplex pump, where the driveshaft powers a crankshaft, subsequently moving plunger rods to pressurize the water. Additionally, identify the engine shaft diameter and whether it is solid or hollow.

Finding a Compatible Replacement Pump

Determine how the flange on your current pump attaches to the motor by measuring the bolt pattern. Ensure that the new pump can be installed as-is. Also, check whether your existing motor is horizontally or vertically shafted, considering whether the pump mounts next to the engine (connected to a horizontal driveshaft) or underneath (connected to a vertical driveshaft).

Now, search for a replacement pump that matches the PSI (pressure rating) and GPM (gallons per minute) of your old pump. While higher values may seem advantageous, it’s crucial not to exceed the engine’s capacity.

Refer to the installation drawings and owner’s manual for replacement pumps similar to your current one. Compare measurements to ensure a proper fit. Although most major engine manufacturers use standardized flange measurements, we advise double checking before making a purchase. If in doubt, contact us before placing an order.

With these step-by-step instructions, you’ll find the proper pump in just a matter of minutes, and be ready to resume your pressure washing activities.