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Replacement Pump Buying Guide

Replacement Pump Buying Guide

Published by Frank on 23rd Nov 2022

So you've decided to look for a new pump for your pressure washer. Before you even get to looking at pressure (psi) and flow rates (gpm) here's the information you need to keep on hand to ensure compatibility.

  1. Engine/motor RPMs: All pumps have a max. RPM (revolutions per minute) rating for how much power they can handle. For direct-drive pumps for gas engines, this is generally 3,400 rpm. This number varies for belt-driven and electric pumps. Ensure that your motor's RPM doesn't exceed the max. rated RPM on your pump. Additionally, you'll get the best possible performance out of your pump by matching the pump's rated power (hp/kW) with the engine or motor's peak power.
  2. Shaft size: All our pumps come in industry-standard shaft sizes. While there may be a few exceptions, most engines and motors conform to these industry standards like SAE J609 for gas engines and NEMA for electric motors. Your engine's/motor's shaft size should match the size of the mounting flange on the pump (for e.g. a ¾-inch shaft on an engine will be compatible with ¾-inch shaft pumps). Belt-driven pumps are the exception here, as they can be powered by both gas engines and electric motors.
  3. Clearance: Since there are no industry standards for pressure washer mounting frames, check the pump measurements (from the specifications) and orientation of the connectors (from the pictures) to ensure there's enough clearance to fit on the frame of your pressure washer.