Hourleey Pressure Washer Pump Replacement 3700 PSI 2.5 GPM — 3/4" Shaft Horizontal Triplex with Adjustable Unloader

Hourleey's horizontal triplex plunger pump delivers up to 3700 PSI and 2.5 GPM as a direct-fit replacement for select Simpson MorFlex models with an adjustable unloader for precise pressure control.

This replacement pump is built to restore or upgrade the performance of gas-powered pressure washers used for heavy-duty cleaning. It follows a standard SAE flange pattern, uses a 3/4" shaft, and includes installation accessories so you can swap pumps without sourcing extra parts. Designed for residential, commercial, and light industrial applications, the unit balances high-pressure capability with practical features such as an oil sight glass and an adjustable unloader valve.

How much cleaning power does this pump provide?

The Hourleey pump achieves a maximum pressure of 3700 PSI and a flow rate up to 2.5 gallons per minute, giving strong impact force and usable water volume for stubborn grime. These specs make it suitable for decks, driveways, equipment, and preparatory surface cleaning before painting. Peak performance depends on correct matching to engine speed, spray nozzle, and hose setup.

• Maximum 3700 PSI for deep cleaning
• Up to 2.5 GPM flow for efficient rinsing
• 3/4" shaft and standard SAE bolt pattern for compatibility

What connections and parts come with the pump for installation?

The pump ships with mounting hardware and fittings to simplify installation: bolts, a shaft key, O-ring washers, flat and spring pads, a vent plug, and a detergent hose. It has a 3/4" garden-hose style inlet and a 3/8" quick-connect outlet to match common pressure-washer plumbing. An instruction sheet is included to guide correct placement and torque of the supplied fasteners.

• Included: bolts (UNF 5/16-24 x 1), shaft key, pads, washers, and vent plug
• Inlet: 3/4" garden-hose compatible connection
• Outlet: 3/8" quick-connect for standard wands and hoses

How does the pump protect itself and stay maintained?

A sight glass on the pump lets you monitor oil level and spot any clouding that indicates water contamination. Hourleey recommends oil changes around every 60 operating hours to preserve seals and plunger lubrication. The unit accepts inlet water up to 40°C (104°F) and a properly set unloader limits pressure spikes to protect valves and spray tips.

• Oil sight glass for quick inspections
• Suggested oil service interval: ~60 hours
• Maximum inlet water temperature: 40°C (104°F)

Will this pump fit my pressure washer and how adjustable is the pressure?

The pump uses a standard SAE bolt pattern and is compatible with Simpson MorFlex models 40224, 40225, 40226 and Santoprene model 41182 when shaft size, engine orientation, PSI/GPM, and inlet/outlet types match. Its adjustable unloader allows you to vary pressure output to suit delicate surfaces or tough build-up without swapping pumps. Always verify orientation and plumbing before purchase to ensure a smooth replacement.

• Compatible with listed Simpson and Santoprene models when specs match
• Adjustable unloader for precise pressure control
• Ensure engine shaft diameter and mounting orientation align

Who is this for? If you own a gas pressure washer that needs a direct-fit pump replacement or an upgrade for stronger cleaning performance—especially units using Simpson MorFlex-style mounts—this Hourleey triplex plunger pump is designed for mechanics, rental shops, property managers, and homeowners comfortable with basic mechanical swaps. It's best for users who can confirm shaft size, mounting flange, and hose fittings before installation and who will perform routine oil checks and service.