Quick verdict
A horizontal axial cam replacement pump rated for 3300 PSI at 2.4 GPM, built for gas washers with a 3/4 inch horizontal engine shaft and the SAE bolt pattern. It suits an owner whose engine still runs fine but whose pump has lost pressure or started leaking. The caveat is the matching homework: shaft size, bolt pattern, engine orientation and the PSI and GPM of the original pump all have to line up.
Strengths
- Rated 3300 PSI at 2.4 GPM, a common mid-range gas washer spec
- Fits 3/4 inch horizontal shafts with the SAE bolt pattern
- Maintenance-free sealed crankcase, no oil changes
- Thermal relief valve protects the pump in bypass
- Anodized die-cast aluminum body resists corrosion
- Hardware and siphon tube in the box
Weaknesses
- Axial cam pumps are shorter-lived than triplex pumps
- Correct fit depends on careful matching of shaft, bolts and ports
- No pump-saver or thread sealant included
- Garden hose inlet only, no 3/4 inch quick-connect option
The overall YardToolLab Score is out of 100. Section scores are out of 10.
Who this pump kit is for
Gas pressure washers usually die from the pump end, not the engine. A Honda or Briggs engine will run for a decade while the axial cam pump behind it loses pressure, weeps at the seals or seizes after a winter of trapped water. The OEM Technologies 90028 is the fix for that situation: a replacement horizontal pump rated for 3300 PSI at 2.4 GPM, sized for the 3/4 inch shaft and SAE bolt pattern that most mid-range consumer gas washers use. OEM Technologies is the pump brand behind many Simpson machines, which is why this listing carries the Simpson name.
This review is based on the maker’s published specifications and on recurring owner feedback. We have not run this product ourselves.
What you get
The kit is the pump, the mounting hardware and a chemical siphon tube. The pump body is anodized die-cast aluminum, the crankcase is sealed and maintenance-free, and a thermal relief valve is fitted. The water inlet is a standard garden hose thread and the high-pressure outlet is a threaded M22 fitting, which the maker says mates with Simpson MorFlex hoses 40224, 40225 and 40226 and the Santoprene 41182. The listing does not state a keyway or a specific list of engine models, so the match comes down to the five checks described below.
Fit and compatibility
Before ordering, confirm the engine is horizontal (the shaft points sideways, not down), measure the shaft at 3/4 inch, and look at the four bolt holes on the engine face for the SAE pattern. Then read the data plate on the old pump: a washer that was sold as 3300 PSI and 2.4 GPM is the ideal candidate, and one within a couple of hundred PSI either way will usually run fine on the same engine. Finally, check that the old pump also used a garden hose inlet and M22 outlet so the existing hose and gun carry over. Owners who skip the shaft measurement and discover a 7/8 inch shaft on delivery are the most common unhappy reviews in this product class.
Pressure and flow
At 3300 PSI and 2.4 GPM the cleaning units come out to about 7900, which is enough for concrete driveways, decks, fences and vehicles with the right tip. These are the maker’s figures at the pump; actual pressure at the nozzle depends on the engine being in good tune and on the hose length. Axial cam pumps run the pistons directly off a wobble plate on the engine shaft, which keeps them compact and affordable but gives them a shorter working life than a belt-driven or triplex pump. For a homeowner washing a few weekends a year, that is a fair trade.
Build and installation
The sealed crankcase means there is no oil to check and no oil to change, which is why the maker calls it maintenance-free. The anodized aluminum housing resists corrosion from water and detergent. Installation is a matter of pulling the old pump, cleaning the shaft, sliding the new pump on with the supplied hardware and torquing the bolts evenly; a little anti-seize on the shaft makes the next swap easier. The thermal relief valve protects the pump when the trigger is off, but the engine should still be shut down during any pause longer than a minute or two.
Living with it
Pump failures on consumer washers almost always trace to water left inside over winter or to running the pump dry. Run pump saver through the inlet before storage, never start the engine without the water on, and keep a spare inlet filter screen. The maker does not state a warranty length in the listing; check the product page before buying. Treat the pump as a wear item with a service life measured in seasons rather than decades.
Alternatives to Consider
The OEM Technologies 90029 is the same pump family at 3400 PSI and 2.5 GPM, the better match for a washer that was originally rated slightly higher. An AR (Annovi Reverberi) axial pump with a 3/4 inch shaft is the usual alternative brand and is worth comparing for availability. If the washer runs a Honda GX200 or similar engine and sees regular heavy use, upgrading to a triplex pump from AAA or CAT costs more but roughly doubles service life.
Verdict
Buy the OEM Technologies 90028 if your gas washer was rated around 3300 PSI and 2.4 GPM, the engine runs well, and the shaft, bolt pattern and ports all match. Skip it if the engine is vertical, the shaft measures 7/8 inch, or the machine gets enough use that a triplex pump would pay for itself.
Full specifications
OEM Technologies 90028 3300 PSI 2.4 GPM Horizontal Axial Cam Pressure Washer Pump Kit, 3/4 in Shaft FAQs
Match five things: a horizontal engine, a 3/4 inch shaft, the SAE bolt pattern on the engine face, a PSI and GPM rating the same as or close to your old pump, and the same inlet and outlet style. If the old pump had a 7/8 inch shaft or a vertical engine, this is not the one.
No. The crankcase is sealed and maintenance-free per the maker. It cannot be topped up or changed, which is convenient but also means the pump is replaced rather than rebuilt when it wears out.
When the trigger is released the pump runs in bypass and the trapped water heats quickly. The valve dumps a little hot water and draws in cooler water so the seals do not cook. It is not a substitute for shutting the engine off during long pauses.
The outlet is a threaded M22 connection. The maker names the Simpson MorFlex 40224, 40225 and 40226 hoses and the Santoprene 41182 as compatible, and most M22 consumer hoses will thread on.
