Which Simpson Gas Pressure Washer Do You Need?
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Simpson is a pressure washer specialist known for gas-powered cold water machines that range from weekend homeowner models to rugged contractor units. If you are buying your first gas pressure washer or picking one as a gift, three terms decide nearly everything: PSI (pounds per square inch, or how hard the water hits), GPM (gallons per minute, or how much water flows, which sets how fast you rinse away dirt) and pump type.
These six models differ mainly in power and build, stepping up from the homeowner Clean Machine with an axial cam pump to PowerShot and Aluminum Series machines with triplex pumps, longer hoses and larger engines.
Simpson Gas Pressure Washers Compared
| Model | Pressure and flow | Engine | Pump | Hose |
|---|---|---|---|---|
| Simpson Clean Machine 3400 | 3400 PSI, 2.5 GPM | 208 cc CRX | Axial cam | 25 ft |
| Simpson PowerShot 3500 | 3500 PSI in title, 3300 PSI in details, 2.5 GPM | Honda GX200 | AAA triplex | 25 ft |
| Simpson PowerShot 4400 | 4400 PSI, 4.0 GPM in title | CRX 420cc | AAA triplex plunger | 50 ft |
| Simpson Aluminum Series 4200 | 4200 PSI, 4.0 GPM | Honda GX390 | CAT triplex plunger | 50 ft |
| Simpson PowerShot 4000 PS60869 | 4000 PSI, 3.5 GPM | Honda GX270 | AAA triplex plunger | 50 ft |
| Simpson Aluminum Series 3600 | 3600 PSI, 2.5 GPM | Honda GX200 | AAA triplex plunger | 35 ft |
Simpson Clean Machine 3400 PSI Gas for Homeowners
Simpson
Simpson Clean Machine 3400 PSI Gas Pressure Washer, 2.5 GPM, CRX engine
Price and specifications are read from the Amazon product page and can change.
Simpson Clean Machine 3400 PSI Gas
Best for: Homeowners washing decks, cars and patios
Pros
- 3400 PSI at 2.5 GPM
- Maintenance-free axial cam pump
- Four quick-connect tips
- Low-oil shutdown
Cons
- Axial pump, not triplex
- Shortest warranty terms listed
The Simpson Clean Machine 3400 PSI Gas pressure washer (model CM61083) is the homeowner model in this group. It pairs a 208 cc CRX engine with low-oil shutdown and an OEM Technologies axial cam pump rated at 3400 PSI and 2.5 GPM. An axial cam pump is a compact, sealed design that the listing calls maintenance-free, and it has a thermal relief valve that releases hot water to help prevent overheating when you pause.
It comes with a 25-foot MorFlex hose that resists kinks, a front-load M22 spray gun, a 16-inch wand and four quick-connect tips: 0, 15 and 40 degrees plus a soap nozzle. The smaller the degree number, the narrower and stronger the spray. The item highlight mentions five nozzles and an AAA pump, which conflicts with the feature list, so expect the four tips named in detail. The steel frame rides on 10-inch pneumatic tires, the listing gives 64 pounds in one place and 61 in another, and the warranty is 2 years on the engine and 1 year each on pump and frame. It is 49-state compliant and not sold in California.
This is the right size for washing decks, driveways, siding, fences, patio furniture and cars a few times a year. Anyone who expects to use a pressure washer weekly, or for paid work, will be better served by the triplex models below.
Simpson PowerShot 3500 PSI Gas Pressure for Serious DIY
Simpson
Simpson PowerShot 3500 PSI Gas Pressure Washer, 2.5 GPM, Honda GX200 Engine
Price and specifications are read from the Amazon product page and can change.
Simpson PowerShot 3500 PSI Gas Pressure
Best for: Serious DIYers wanting a triplex pump
Pros
- Honda GX200 engine
- AAA triplex pump with unloader
- Five quick-connect tips
Cons
- PSI listed as 3500 and 3300
- 25 foot hose only
The Simpson PowerShot 3500 PSI Gas Pressure washer (model PS61002-S) steps up to a Honda GX200 engine with low-oil shutdown and an AAA triplex pump with an integrated unloader and thermal relief. A triplex pump uses three plungers and is generally built for longer service life and repair, which is why pros prefer it. The unloader redirects water when you let go of the trigger.
There is a pressure mismatch to note: the title says 3500 PSI, while the feature list and description say 3300 PSI at 2.5 GPM. Weight is listed as both 74 and 72.8 pounds. It includes a 25-foot MorFlex hose with a non-marring polyurethane jacket, a rear-load M22 gun, a 16-inch wand, five tips (0, 15, 25, 40 degrees and soap) and 10-inch tires on a powder-coated steel frame. The listing does not give warranty terms.
This suits a homeowner who wants a longer-lasting pump or who cleans often, as well as light contractor use. For large commercial jobs, the 4.0 GPM models finish faster.
Simpson PowerShot 4400 PSI Gas Pressure for Big Contractor Jobs
Simpson
Simpson PowerShot 4400 PSI Gas Pressure Washer, 4.0 GPM, CRX 420cc Engine
Price and specifications are read from the Amazon product page and can change.
Simpson PowerShot 4400 PSI Gas Pressure
Best for: Contractors doing big decks and paint prep
Pros
- 4400 PSI at 4.0 GPM in title
- 50 foot Monster hose
- 13 inch tires
Cons
- Description quotes different specs
- Heavy machine
The Simpson PowerShot 4400 PSI Gas Pressure washer (model PS60843) is listed with a CRX 420cc engine and an AAA industrial triplex plunger pump delivering 4400 PSI at 4.0 GPM, plus PowerBoost Technology for higher pressure at the nozzle. It is aimed at contractors doing deck cleaning, wood restoration and paint preparation.
It comes with a 3/8-inch by 50-foot Monster hose, five quick-connect tips, an ergonomic gun and a 31-inch wand, all on a welded steel frame with 13-inch tires. Be careful with the description, though: it describes a 4000 PSI, 3.5 GPM machine and names model PS60869, which is a different product in this list. The item weight is given as 61.23 kg. The listing notes the machine is factory tested and may arrive with a little fuel or oil odor, and it does not ship to California.
Choose this for professional-level output from a steel-frame machine. If you prefer a Honda engine and a longer written warranty, the Aluminum Series 4200 is the alternative.
Simpson Aluminum Series 4200 PSI Gas for Heavy Professional Use
Best for: Lighter pro machine that is easy to move
Pros
- 3600 PSI at 2.5 GPM
- Aluminum frame
- 35 foot hose
- 10 year frame warranty
Cons
- Listing also says steel frame
- Lower flow than 4.0 GPM models
Simpson
Simpson Aluminum Series 4200 PSI Gas Pressure Washer, 4.0 GPM, Honda GX390
Price and specifications are read from the Amazon product page and can change.
Simpson Aluminum Series 4200 PSI Gas
Best for: Pros wanting a CAT pump and long warranty
Pros
- Honda GX390 engine
- CAT triplex plunger pump
- 5 year pump warranty
- Aluminum frame
Cons
- Heaviest at 133 lb
- More power than homes need
The Simpson Aluminum Series 4200 PSI Gas washer (model ALH4240) uses a Honda GX390 engine with low-oil shutdown and a CAT triplex plunger pump rated at 4200 PSI and 4.0 GPM. The listing mentions advanced oil seal technology and ceramic-coated pistons to extend seal life, plus thermal relief.
It includes a 50-foot Monster dual-braided hose with a non-marring jacket, a professional spray gun with a safety lock-out, a 16-inch wand and five tips. The frame is aircraft-grade aluminum, which resists corrosion, and rolls on 13-inch tires. It is still the heaviest here at 133 pounds. The warranty is 3 years limited commercial on the engine, 5 years on the pump and 1 year on the frame.
This suits contractors and facility or fleet crews who run a machine for hours. It is far more than most homeowners need, and the Clean Machine or PowerShot 3500 are easier to store.
Simpson Cleaning PS60869 PowerShot 4000 PSI for Prosumers
Best for: Prosumers cleaning concrete and fleets
Pros
- 4000 PSI at 3.5 GPM
- Honda GX270 engine
- 50 foot hose
- 31 inch wand
Cons
- 120 lb to move
- Warranty length not specified
The Simpson Cleaning PS60869 PowerShot 4000 PSI washer uses a Honda GX270 engine and an AAA industrial triplex plunger pump rated at 4000 PSI and 3.5 GPM, with thermal relief and PowerBoost Technology. The listing calls it direct drive, meaning the pump attaches straight to the engine shaft.
You get a 3/8-inch by 50-foot Monster hose, five quick-connect tips, an ergonomic gun and a 31-inch wand, with 13-inch tires on a welded steel frame. It measures 38 by 23.5 by 29 inches and weighs 120 pounds, and uses a threaded M22 pump and hose connection. The warranty is only listed as “Warranty.”
This fits prosumers who clean large driveways, farm equipment or fleets and want Honda power between the mid-range and top models. If you need maximum flow, the 4.0 GPM models move more water.
Simpson Aluminum Series 3600 PSI Gas for Easy Transport
The Simpson Aluminum Series 3600 PSI Gas washer (model ALH3425) pairs a Honda GX200 engine with a maintenance-free AAA triplex plunger pump rated at 3600 PSI and 2.5 GPM, with an integrated unloader, thermal relief and PowerBoost.
It includes a 35-foot MorFlex 5/16-inch hose, a professional gun with safety lock-out, a 16-inch wand and five tips, on 10-inch tires. The frame is described as aircraft-grade aluminum in the features and description, though the item highlight says steel, so rely on the more detailed aluminum wording. It weighs 78 pounds, and the warranty is 3 years on the engine, 5 years on the pump and 10 years on the frame, the longest frame coverage listed here.
This is a good fit for a small crew or detail-oriented homeowner who lifts the machine into a truck often. For heavier jobs at higher flow, the 4.0 GPM Aluminum Series 4200 takes over.
How to Choose the Right Simpson Gas Pressure Washer
Match PSI and GPM to the job. Around 3400 PSI at 2.5 GPM, like the Clean Machine, handles most home cleaning. For wide driveways, paint stripping or daily work, 4.0 GPM models like the PowerShot 4400 and Aluminum Series 4200 rinse faster. If you are also comparing smaller units, our guide to the Simpson 3200 PSI pressure washer covers a lighter option.
Choose a pump for how often you will use it. Axial cam pumps are compact and fine for occasional use. Triplex pumps, found on every model here except the Clean Machine, are built for longer life.
Check hose length and weight. A 50-foot hose lets you reach around a house without moving the machine, but heavier units like the 133-pound Aluminum Series 4200 are harder to load. If you only wash cars and patio furniture, an electric power washer may be simpler.
Finally, read the warranty. The Aluminum Series listings give the clearest pump and frame coverage.
FAQ
What is the difference between PSI and GPM?
PSI is the force of the water, which loosens dirt. GPM is the volume of water, which carries dirt away. Multiplying them gives a rough sense of cleaning speed.
What is a triplex pump?
A triplex pump uses three plungers to build pressure. It is usually more durable and serviceable than an axial cam pump, and five of these six models use one.
Can I buy these in California?
The listings describe these machines as 49-state compliant and say they are not for sale or shipping to California.
Which Simpson is best for washing a car?
The Clean Machine 3400 is sized for homeowners and includes a 40-degree tip and soap nozzle suited to cars. Avoid the 0-degree tip on paint.
Why do some listings show different PSI numbers?
The PowerShot 3500 listing gives both 3500 and 3300 PSI, and the PowerShot 4400 description quotes another model’s specs. Confirm the model number on the product box.
Which Simpson pressure washer should I buy as a gift?
For a homeowner, the Clean Machine 3400. For a hobbyist who wants a triplex pump, the PowerShot 3500. For a contractor, the Aluminum Series 4200 or PowerShot 4400.
