Illustrated label for SIMPSON 90027; not a product photograph
SIMPSON / Pumps

SIMPSON OEM Technologies Axial Cam Pump Kit 90027

3,300 PSI · 2.4 GPM · 7/8 in shaft.

3,300 PSI2.4 GPM7/8 in shaft

The SIMPSON 90027 is a replacement OEM Technologies axial cam pump kit rated 3,300 PSI at 2.4 GPM, for engines with a 7/8 in vertical shaft. It has a garden-hose inlet and a threaded M22 outlet.

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Specifications at a glance

BrandSIMPSON
Part number90027
PumpOEM Technologies axial cam
Engine shaft orientationvertical
Shaft diameter7/8 in
Max pressure3,300 PSI
Max flow2.4 GPM
InletGarden hose
High-pressure outletthreaded M22
Manifoldbrass
Unloaderintegrated with Easy Start
Warranty1-year

From SIMPSON's pump catalog. Anything SIMPSON doesn't state is marked as not stated.

What to know about the 90027

Shaft and orientation

The pump slides onto the engine crankshaft, so the shaft must be 7/8 in and vertical. Check your engine manual or measure the shaft before ordering.

Match the rating

SIMPSON's guidance is to match engine orientation, PSI, GPM, shaft diameter and the inlet and outlet connections of your current pump. This kit is rated 3,300 PSI at 2.4 GPM; after any pump change, size your nozzles to the new rating with the nozzle size calculator.

Outlet and hose

The outlet is threaded M22, so it takes the M22 hoses most homeowner gas washers use, such as MorFlex.

Key features (from SIMPSON)

  • OEM Technologies axial cam pump
  • 3,300 PSI at 2.4 GPM
  • 7/8 in shaft, vertical engines
  • Brass manifold
  • Unloader: integrated with Easy Start
  • Garden-hose inlet, threaded M22 outlet
  • 1-year warranty

Is it right for you?

Good choice ifyour engine has a 7/8 in vertical shaft and your washer was rated close to 3,300 PSI at 2.4 GPM
Look elsewhere ifyour engine shaft is not 7/8 in
Look elsewhere ifyour engine is horizontal-shaft
Look elsewhere ifyour hose uses quick-connect fittings and you don't want adapters

Questions about the 90027

Will the SIMPSON 90027 fit my pressure washer?

It fits engines with a 7/8 in vertical shaft and the standard SAE bolt pattern, on washers rated around 3,300 PSI at 2.4 GPM. Check your engine shaft and your current pump's inlet and outlet first.

Do I need new nozzles after changing the pump?

Only if the new pump's rating differs from the old one. Work out the right size for 3,300 PSI at 2.4 GPM with the nozzle size calculator.

Does the 90027 need oil?

Axial cam pumps like this are usually sealed; check the manual for your kit.

What to check before buying

Measure before you order. Confirm the engine shaft diameter and orientation, that your washer's original rating is close to 3,300 PSI at 2.4 GPM, and that your hose matches the threaded M22 outlet.

Other 7/8 in shaft pump kits

All replacement pumps

Source and editorial status

Manufacturer reference: SIMPSON pump catalog ↗. Specifications checked 3 November 2026. We have not tested this product.

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