WOJET Triplex Plunger Pressure Washer Pump 4400 PSI 4.0 GPM — 1-inch Shaft Self-Priming Replacement for 9–15HP Engines

This replacement pump kit swaps into many commercial and residential gas pressure washers to restore lost pressure and flow. Designed for compatibility with popular engines and models such as Honda GX270/GX340, Simpson PS60869, DeWalt 4000/4200 PSI series and other 9–15 HP platforms, the WOJET Triplex prioritizes continuous cooling, durability, and flexible water sourcing for demanding jobs.

How does this pump bring my pressure washer back to peak performance?

The WOJET Triplex is an industrial‑grade, high‑flow plunger pump rated at 4400 PSI and 4.0 GPM, engineered to match the output range of many gas washers. Upgrading to this pump restores original cleaning force and steady flow, improving performance on driveways, siding, and equipment cleaning.

• Triplex ceramic pistons for consistent high‑pressure output
• Forged brass manifold and brass pump head for corrosion resistance
• Pre‑filled oil and sealed construction to reduce maintenance
• Adjustable unloader knob to tune operating pressure

What safety and longevity features prevent overheating and damage?

An integrated unloader valve instantly diverts flow when the trigger is released, creating a continuous water circulation that dissipates heat instead of allowing temperatures to spike. This constant cool‑down path reduces thermal stress on seals and valves, extending service life compared with pumps that stall the flow.

• Integrated unloader for continuous cooling when idle
• Polished ceramic plungers that resist wear under load
• Powder‑coated aluminum crankcase to resist corrosion and impacts
• Included siphon tube and mounting hardware to aid installation

Can I use non‑tap water sources with this pump?

Yes — the WOJET Triplex offers a self‑priming design so it can draw water from buckets, tanks, or pools when a direct faucet hookup isn’t available. That makes the pump ideal for mobile cleaning, remote jobs, or construction sites where water access varies.

• Self‑priming capability for flexible water sourcing
• 3/4" garden‑hose inlet compatibility for common supplies
• Siphon tube included to facilitate bucket or tank draws
• Quick‑connect 3/8" outlet for fast hose attachment

Which engines and models will this kit replace, and how do I confirm fit?

The kit is intended for 9–15 HP (250–420 cc) horizontal‑shaft engines with a 1" shaft and is commonly used as a replacement for Honda GX270/GX340/GX390 applications and many Simpson, DeWalt, Kohler, Westinghouse, Generac, and aftermarket models. To ensure compatibility, compare shaft size, mounting bolt pattern, PSI/GPM specifications, and engine orientation.

• Compatible with Honda GX270, GX340, GX390 and similar 1" shaft engines
• Fits many Simpson PS series and DeWalt 4000/4200 models
• Confirm by matching PSI/GPM, shaft diameter, and bolt layout
• Manufacturer offers fit verification—send brand and model if unsure

Who this product is for: If you operate or maintain gas pressure washers used for heavy residential, light commercial, or jobsite cleaning and you need to restore lost pressure, reduce downtime from overheating, or enable water sourcing without a faucet, the WOJET Triplex pump kit is built for you. It suits owners of 9–15 HP horizontal engines, service shops replacing worn pumps, and contractors wanting reliable, high‑flow performance with easy installation features and long‑life materials.