Simpson Pro Series 4000 PSI Pressure Washer Review

Simpson Pro Series Pressure Washer

The Simpson Pro Series 4000 PSI Pressure Washer Makes Outdoor Cleaning Easy

We’ve been testing Simpson pressure washers for years and have certainly come to appreciate their quality and value. Simpson has been serving professionals for a long time, so the Pro series isn’t really a completely new category for them. However, there are some differences that make the Simpson Pro Series 4,000 PSI Pressure Washer an incredibly compelling option.


  • Plenty of power for most jobs
  • Adjustable GPM
  • AAA Triplex pump
  • All steel frame
  • Long wand with swiveling secondary handle


  • No significant drawbacks

Simpson Pro Series 4000 PSI Pressure Washer Performance

Simpson Pro Series Pressure Washer
  • Max PSI: 4000
  • Flow Rate: 3.5 GPM
  • Nozzles: 0°, 15°, 25°, 40°, and soap nozzle

Cleaning Power

At its heart, this pressure washer is powered by Simpson’s brand new OEM CRX 340 engine (we’ll talk more about this later). It tops out at 4,000 PSI and has a max flow rate of 3.5 GPM, putting it right in line with some of their Honda powered models.

With those specs in mind, I paired this machine with our Simpson 20-inch surface cleaner and got to work cleaning our back patio area here at the office. Not surprisingly, this pressure washer helped me power through years of organic buildup and left a clean surface in its wake.

Simpson Pro Series Pressure Washer

Next, I switched over to the kitted 52-inch wand to clean up some of the decorative pavers. Once again, the PS61371 performed beautifully. The longer wand helped to put some extra distance between me and the surface, and also limited excessive bending while cleaning horizontal surfaces, like sidewalks. Additionally, the swiveling forward handle made it easy to maneuver and control the wand.

Simpson includes a siphon hose that attaches directly to the AAA triplex pump if you’d like to downstream chemicals while you’re cleaning.

Simpson Pro Series 4000 PSI Pressure Washer Design Notes

Simpson Pro Series Pressure Washer
  • Model: Simpson Pro PS61371
  • Power Source: Simpson CRX 340 engine
  • Fuel Type: Gasoline
  • Oil Type: 10W-40
  • Tires: 13 in. pneumatic


Simpson opted for a corrosion resistant, powder-coated steel tube frame construction. This is especially crucial towards extending the working life of your machine when incorporating chemicals into your cleaning process.

Personally, the handle height is spot on for me. It stands 29 inches tall, making it easy to transport without much excessive bending. Its open-frame design of the machine keeps the engine very easy to access. Getting to areas you frequently access, such as the oil reservoir, is simple.


The pump choice is a quick indicator between professional and residential pressure washers. Pro models normally feature triplex pumps, while lighter-duty models typically utilize axial cam pumps.

AAA Triplex pump

The AAA triplex pump featured on this Pro series is built for heavy-duty professional use. These pumps undergo CETA CPC-100 certification testing for pressure and flow, giving us a tremendous amount of confidence that the ratings Simpson gives are what we’ll experience in the field. Moreover, the PSI is adjustable, so you can customize it to fit your needs.

Simpson CRX Engines

The CRX engines are designed for heavy-duty professional use. It has all the key features Pros looks for, including easy starting, reliable performance, and a low oil engine shutdown. The team that developed the CRX engine is so confident in its long-term reliability that it includes a 5-year warranty—the best in the industry and two years longer than what Honda offers.

These engines aren’t just for pressure washers, though. There are also generators, semi-trash pumps, and chemical pumps that come with CRX engines. Plus, they’re an excellent option when it’s time to repower other equipment.

Simpson Pro Series 4000 PSI Pressure Washer Price

You can find this Simpson Pro pressure washer exclusively at Lowe’s for $799. It comes with a non-marring MorFlex 3/8-inch x 50-foot hose, siphon hose, five nozzles, and a 52-inch wand. In addition to the 5-year warranties on the engines and pumps, the frame also carries a 10-year warranty.

The Bottom Line

If you’ve been using a mid-range pressure washer at home or on the job, give the Simpson Pro Series PS61371 a try. Their new OEM power source and AAA triplex pump put quality, performance, and longevity at the forefront. Compared to lower-cost options, Simpson’s performance boost will legitimately save you time, making you more productive and profitable.

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