Pressure Washer Pump Finder

Use published shaft, orientation and output data to narrow a replacement-pump search. This finder is intentionally conservative: a matching result is a documented candidate, not a guarantee that it will fit your pressure-washer frame and plumbing.

Initial verified dataset

This first release filters a small set of current manufacturer-documented pump classes from SIMPSON, General Pump, AR North America and Cat Pumps. Unknown is a valid result. If you know the washer mainly as “Honda-powered,” use the Honda engine-family guide first to identify the drive-side details that matter.

Dataset reviewed: August 28, 2026.

Filter documented replacement-pump candidates

Choose the drive-side details you know. Output requirements can narrow the list, but they do not override the mechanical checks.

Engine shaft orientation Look at the engine shaft itself—not the direction the hose leaves the pump. Shaft diameter Measure the actual engine/motor shaft or use the engine specification. Known engine family (optional) An engine example improves confidence in the drive-side class, but does not prove pressure-washer-frame fit. Original / required PSI (optional) Use the original machine/pump rating when possible—not a desired upgrade number. Original / required GPM (optional) Flow affects pump displacement and engine load; closer is usually more useful than simply higher.

Results update automatically as you change the inputs.

How the finder decides what to show

Hard filter

Orientation and shaft diameter

If you specify a shaft orientation or diameter, candidates that conflict with the manufacturer's published data are removed.

Capacity filter

Published PSI and GPM

If you enter the original requirements, pumps that cannot meet them are removed. Higher capacity is not labeled an upgrade or automatically preferred.

Evidence boost

Manufacturer-listed engine example

When the manufacturer explicitly names your engine family for that pump, the result identifies that evidence. Final washer fit still remains conditional.

Final check

Mounting, ports, power & clearance

The finder cannot see your frame or plumbing. Verify flange/bolt pattern, shaft length/keying, RPM, torque/HP, inlet/outlet orientation, unloader and physical clearance before purchase.

Dataset reference table

Model	Orientation	Shaft	PSI	GPM	Published engine / drive evidence
SIMPSON OEM 90026	Vertical	7/8"	3100	2.4	Honda GCV160/170 example
SIMPSON OEM 90028	Horizontal	3/4"	3300	2.4	Kohler SH270; Honda GC160/190 examples
SIMPSON OEM 90029	Horizontal	3/4"	3400	2.5	Honda GC190; Honda GX200 examples
SIMPSON AAA 90036	Horizontal	3/4"	3200	2.8	Honda GX200 example
SIMPSON AAA 90039	Horizontal	1"	4000	3.5	Honda GX270 example
SIMPSON AAA 90034	Horizontal	1"	4400	4.0	Honda GX390 example
General Pump EZ4040G	Horizontal direct-gas class	1" hollow	4000	4.0	SAE J609B; 3400 RPM; 16.4 GHP
AR RSV4G40-PKG	Horizontal	1" hollow	4000	4.0	F40 direct-gas shaft; 3400 RPM; 11 EBHP
Cat Pumps 4DNX25GSI	Horizontal	3/4" straight	3000	2.5	SAE J609 Flange A Extension 3; 3450 RPM

What this finder intentionally does not do

It does not infer a guaranteed fit from a shared shaft diameter, and it does not treat “more PSI” as better. It also does not claim machine-by-machine pressure-washer coverage unless reliable manufacturer model/parts evidence supports it.

Technical sources used by the finder

Frequently asked questions

Does the Pump Finder guarantee that a replacement pump will fit?

No. The finder filters a limited set of manufacturer-documented pump candidates by published orientation, shaft and output data. Final machine compatibility still requires mounting, shaft length/keying, RPM, engine torque or horsepower, inlet/outlet orientation, plumbing, unloader and clearance checks.

Why does the finder show conditional results instead of compatible?

Most manufacturer replacement pages describe a pump class or list example engines, but they still require machine-specific checks. The finder preserves that uncertainty instead of converting a plausible candidate into a guaranteed fit.

What if my pump or pressure washer is not in the finder?

An absent model means only that it is not in this initial verified dataset. It does not mean no replacement exists. Use the advanced specifications and manufacturer documentation, or contact the manufacturer with the exact machine and pump model.

Why are PSI and GPM optional in the finder?

They help narrow the output class, but mechanical compatibility comes first. A pump with enough PSI can still be wrong because the shaft, orientation, flange, RPM, engine power or plumbing do not match.

Can I use the finder to upgrade my pressure washer?

The finder is designed for replacement selection, not performance upgrades. Do not increase flow or pressure beyond the engine and complete system ratings without manufacturer-supported engineering guidance.

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