Quick verdict
A horizontal axial cam replacement pump rated for 3400 PSI at 2.5 GPM, with stainless steel pistons, a sealed crankcase and a thermal relief valve, built for 3/4 inch horizontal shafts such as the Honda GX190 and GX200. It suits a Simpson or similar washer owner whose engine is healthy and whose pump is not. The caveat is that it is still an axial pump, so it is a repair measured in seasons rather than a lifetime upgrade.
Strengths
- Rated 3400 PSI at 2.5 GPM, matching many Simpson MegaShot washers
- Named fit for Honda GX190 and GX200 horizontal engines
- Stainless steel pistons for longer seal life
- Sealed, maintenance-free crankcase with no oil changes
- Thermal relief valve for bypass protection
- Hardware and siphon tube included
Weaknesses
- Axial cam design wears faster than a triplex pump
- Fit still depends on matching shaft, bolt pattern and ports
- No warranty length stated in the listing
- Sealed crankcase cannot be rebuilt
The overall YardToolLab Score is out of 100. Section scores are out of 10.
Who this pump kit is for
A gas pressure washer that starts and runs but no longer builds pressure is almost always a pump problem, and on a Simpson-class machine with a Honda GX190 or GX200 engine the pump costs a fraction of the whole washer. The OEM Technologies 90029 is the replacement for that class: a horizontal axial cam pump rated for 3400 PSI at 2.5 GPM, with a 3/4 inch shaft bore and the SAE bolt pattern. OEM Technologies pumps are the ones fitted to many Simpson washers at the factory, so this is as close to a like-for-like swap as the aftermarket gets.
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 contains the pump, mounting hardware and a detergent siphon tube. The body is anodized die-cast aluminum, the pistons are stainless steel, the crankcase is sealed and maintenance-free, and a thermal relief valve is built in. The inlet takes a garden hose and the outlet is a threaded M22 fitting that the maker says mates with the Simpson MorFlex 40224, 40225 and 40226 hoses and the Santoprene 41182. The listing does not give a weight, a warranty term or a keyway specification, so keep the old pump handy for comparison until the new one is bolted on.
Fit and compatibility
Five checks decide whether this pump is right: the engine must be horizontal, the shaft must measure 3/4 inch, the engine face must carry the SAE four-bolt pattern, the old pump’s PSI and GPM should be the same or close, and the inlet and outlet style should match so the existing hose and gun carry over. The Honda GX190 and GX200 are named by the maker, and the same shaft and bolt pattern appear on several Chinese-built clone engines. Owners who get it wrong almost always missed the shaft measurement, since 7/8 inch shafts look nearly identical at a glance.
Pressure and flow
At 3400 PSI and 2.5 GPM this pump sits in the sweet spot for home use: enough pressure to lift stains from concrete with a 15 or 25 degree tip, and enough flow to rinse a driveway without crawling. These are the maker’s ratings at the pump head, and they assume an engine in good tune and a hose of normal length. Axial cam pumps drive the pistons directly from a wobble plate on the engine shaft, which makes them compact and inexpensive but limits service life compared with a triplex pump. The stainless steel pistons are meant to stretch seal life, which is the usual failure point.
Build and installation
There is no oil to fill, which removes one installation step and one source of future leaks, but it also means the pump is replaced rather than rebuilt at the end of its life. Installation is straightforward: remove the old pump, clean and lightly grease the shaft, slide the new pump on, fit the supplied bolts and tighten them evenly. The thermal relief valve dumps a little hot water when the trigger has been closed for a while; it protects the seals but does not replace shutting the engine off during long pauses.
Living with it
Most axial pump deaths come from water frozen inside over winter or from starting the engine before the water is on. Pump saver before storage, a flowing hose before every start and a clean inlet screen will carry this pump through many seasons of weekend use. Check the product page for the warranty term, since the listing does not state one.
Alternatives to Consider
The OEM Technologies 90028 is the same family at 3300 PSI and 2.4 GPM, the closer match for washers originally rated at that level. An AR (Annovi Reverberi) RMV series axial pump with a 3/4 inch shaft is the usual competing brand and is worth comparing on availability. For a washer that works most weekends, a triplex pump from AAA or CAT with a 3/4 inch shaft costs more up front but is rebuildable and typically outlasts two or three axial pumps.
Verdict
Buy the OEM Technologies 90029 if your washer runs a GX190, GX200 or similar 3/4 inch horizontal engine, was rated around 3400 PSI, and the pump is the only thing wrong with it. Skip it if the shaft is 7/8 inch, the engine is vertical, or the machine sees enough use that a triplex pump makes more sense.
Full specifications
OEM Technologies 90029 3400 PSI 2.5 GPM Horizontal Axial Cam Pressure Washer Pump Kit, 3/4 in Shaft FAQs
The maker names horizontal engines with a 3/4 inch shaft such as the Honda GX190 and GX200, and the SAE bolt pattern. In practice that covers many Simpson MegaShot and PowerShot models and a number of other brands using the same engine class. Confirm your old pump's shaft size and ratings before ordering.
Usually yes. A 100 PSI and 0.1 GPM difference is within what the same engine can drive, and the washer will simply run at the new pump's rating. Match the shaft, bolts and ports first; the PSI figure is the least sensitive of the five checks.
The listing refers to a stainless steel integrated support for an easy-start system, which on these pumps relieves pressure in the head so the engine pulls over without fighting a water lock. It is a convenience, not a guarantee of first-pull starts on a cold engine.
Not to the crankcase, which is sealed. The real maintenance is on your end: keep water flowing before the engine starts, never run it dry, and put pump saver through it before winter storage.
