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Simpson ALH4240 - 4200 PSI 4 GPM Gas Pressure Washer With Honda Engine

The Simpson Aluminum ALH4240 is a gas-powered pressure washer offering a maximum water pressure of 4200 PSI and flow of 4 GPM. (Read full specs)

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Simpson ALH4240 4200PSI Gas Pressure WasherSimpson ALH4240 4200PSI Gas Pressure WasherSimpson ALH4240 4200PSI Gas Pressure WasherSimpson ALH4240 4200PSI Gas Pressure Washer
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Price History
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Price history for the Simpson ALH4240
Latest updates:
  • $1,329.99 - May 16, 2024
  • $1,399.99 - May 1, 2024
Data source: acmetools.com
Since: May 1, 2024
  • Highest Price: $1,399.99 - May 1, 2024
  • Lowest Price: $1,329.99 - May 16, 2024

Features and Specifications

FuelGas-Powered
HandlingWheelbarrow
WaterCold (100°F max.)
PSI4200
GPM4
Cleaning Units16800
Engine389cc 11.7 HP Honda GX390 OHV 4-stroke
PumpCAT Triplex
SeriesAluminum
Other model numbers60688
FrameAluminum
Soap injectionVia siphon hose
Nozzles0°, 15°, 25°, 40°, Soap
Quick connect nozzlesYes
Onboard storageYes
Hose50 ft, ⌀3/8
Hose storageHooks
Dimensions
(L x W x H)
Approx. 38 x 23.5 x 26 in
Weight133 lbs
Pressure controlDial-N-Wash® + unloader valve
Wheels2 wheels, ⌀13", pneumatic
Included accessoriesOil, steel wand, spray gun, high pressure hose, soap hose, 5 nozzles, Dial-N-Wash® pressure regulator
SecurityLow oil, trigger lock and thermal relief valve
EmissionsEPA
Warranty10 years
UPC879399001345

Unlike many websites, we did our best to research each of the specs above. That being said, we are not immune to making the occasional mistake or omission. Should you notice any missing or incorrect values, don't hesitate to suggest improvements so we can address the issue.

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Description

The SIMPSON ALH4240 is designed to meet the rigorous demands of the cleaning pro. Heavy-duty pressure washers with flow and reliability. Perfect for contractors who specialize in deck cleaning, wood restoration, paint preparation, graffiti removal, and all other professional cleaning services. (source: Simpson (opens in a new tab))

Zoom on the Simpson ALH4240

In summary, the Simpson ALH4240 is a heavy duty, commercial pressure washer, that offers an all-around versatile cleaning experience, and also:

  • focused spot cleaning on hard, unpainted surfaces, accessing high spots, and efficiently eliminating stubborn stains
  • general cleaning of hard surfaces , washing vehicles, and preparing surfaces for painting
  • gentle cleaning for sensitive surfaces, and wide coverage cleaning with low pressure
  • applying detergent and cleaning solutions, and rinsing surfaces

Ahead are presented its power characteristics and design, its main features and any other additional features.

Power

The Simpson ALH4240 in use

The Simpson ALH4240

Powered by an impressive 389cc (11.7 hp) engine, its triplex pump can deliver a pressure of 4200 PSI (around 70 times more than a standard garden hose) and a flow of up to 4 GPM (CETA-certified values). With these values combined, the Simpson ALH4240 boasts a cleaning power of 16800 Cleaning Units.

For this gas-powered pressure washer, the Honda GX390 engine is started using a time-tested pull-start mechanism.

Gasoline is stored in a steel fuel tank with a maximum capacity of 1.6 gallon.

Design & Handling

With its wheelbarrow-inspired design, the Simpson ALH4240 aims for excellent mobility and stability, enabling effortless maneuvering and dependable performance across diverse environments. Featuring an aluminum frame, this pressure washer boasts easy handling and exceptional durability, thanks to its corrosion-resistant properties and lightweight construction. The handle adds to the ALH4240 convenience of transport.

With its weight clocking in at 133 lbs, this unit's heftiness can't be ignored, presenting significant difficulties for users who need to lift and transport it, especially over uneven terrain. The major reasons for its heavy weight are its 389cc Honda GX390 engine, the triplex pump and aluminum frame. Nevertheless, with its two 13" pneumatic wheels, users can manage the ALH4240 with less difficulty, even over uneven terrain.

Main Features

The Simpson ALH4240 in use

The Simpson ALH4240

The Simpson ALH4240's package includes a spray gun, a wand, a pressure hose, 5 nozzles and a detergent injection feature, with a more detailed description below.

  • Soap injection: Even without a built-in soap tank, the device relies on a siphon hose to provide detergent. Connection of a soap nozzle triggers the pressure washer to automatically incorporate the detergent into the water stream.
  • Pressure hose: With a set of convenient hooks, the unit provides a convenient way to store the included 50 ft ⌀3/8" high-pressure hose when not in use, keeping it organized and readily accessible.
  • Spray gun and wand: A side hook allows for an easy storage of the included classic ergonomic spray gun and its steel wand.
  • Nozzles: Below, you'll find a table outlining the 5 included nozzles and their recommended surfaces.


15°

25°

40°

Soap
Concrete, brick, masonryUse with cautionSuitableSuitableSuitableSuitable
Siding, gutters, houseNot recommendedUse with cautionUse with cautionSuitableSuitable
Fencing, deck, patioNot recommendedUse with cautionUse with cautionSuitableSuitable
Lawn equipment, boat, RVNot recommendedUse with cautionUse with cautionUse with cautionSuitable

Important: The nozzle shapes shown above are for illustrative purposes and may vary. Symbols denote suitability, with a red cross indicating 'Not recommended,' a green check for 'Suitable,' and an orange check for 'Use with caution.'

Other Features

Some of the accessories of the Simpson ALH4240

Some of the included accessories

  • Dial-N-Wash®: Simpson’s Dial-N-Wash® is an adjustable pressure regulator that allows you to choose a desired pressure for your specific cleaning application. High, medium and low pressure settings can be switched between easily by a simple twist. Its design assures its compatibility with most pressure washer standard spray wands and standard guns with threaded fittings.
  • Onboard storage: With the Simpson ALH4240's handy storage area, you’ll always have all the necessary nozzles and accessories at hand and thus, you’ll be fully prepared for any job.
  • Safety: Safety of operation is enhanced by a thermal relief valve (which helps to prevent internal pump damage), a low oil protection and a trigger lock mechanism (which prevents accidental operation).
  • Accessories: Besides the usual owner's manual (opens in a new tab) and documentation to get you promptly started, the Simpson ALH4240 comes with soap hose, oil, pressure hose, wand, pressure regulator and spray gun.

Product Videos

The Simpson ALH4240's performance versus other pressure washers

The following charts are provided to give you an idea of how the key specs of the Simpson ALH4240 compare to similarly priced pressure washers.

  • Able to deliver a maximum pressure of 4200 PSI, the Simpson ALH4240 is one of the gas-powered products that produce an above average water pressure, in the $1100 to $1500 price range. If the highest possible power of the water stream is your priority, one of the champions in this price range is the Lifan LFQ4515E-CA with 4500 PSI.
  • At 4 GPM, this washer stands as one of the premier choices in the aforementioned price range, offering a high volume of water.
  • Featuring 16800 Cleaning Units (PSI X GPM) in total, the ALH4240 ranks among the more efficient options in its respective price bracket. When considering the importance of superior cleaning power, the Lifan LFQ4515E-CA stands out with its 18000 Cleaning Units, boasting one of the highest cleaning efficiencies among similarly priced units.
According to our stats, the following comparison is pretty popular: Simpson ALH4240 vs Simpson PS4240.

Price comparison

As you can see from these interactive charts, when compared to other gas-powered washers between 16500 and 17000 Cleaning Units, the Simpson ALH4240 is on the average side of the price range.

Therefore, this pressure washer nicely fits in the expected budget for this kind of cleaning power.

The bottom line

STRENGTHS:
  • In the expected price range
  • 10 year (limited) warranty
  • Triplex pump
  • Honda engine
  • Designed to be stable
  • Aluminum frame
  • Good range of nozzles included
  • Onboard storage
  • Several security features
  • High PSI for the price
  • High GPM for the price
  • High CU for the price
WEAKNESSES:
  • No soap tank

Do you own the Simpson ALH4240 and agree (or disagree) with these strengths and weaknesses?

Let us know and write your own review.

About Simpson

Simpson has over 50 years of experience making quality products for the outdoor power equipment industry. Part of the FNA Group based in Pleasant Prairie, Wisconsin since 2006, they are a vertically-integrated company, meaning most of the parts and accessories are manufactured and assembled by them. Their manufacturing facilities are international, but their gas-powered pressure washers are made in the USA. With the company motto "Driven by Performance", Simpson continues to offer a great variety of pressure-washing systems for the homeowner or the professional contractor.

Warranty Information

The Simpson ALH4240 is covered under a warranty for up to 10 years. This warranty may be limited and may not cover all parts of the unit.
For more information about the warranty of Simpson pressure washers, please contact the Simpson Customer Support: 1-877-362-4271.

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