Biswing Pressure Washer Pump Replacement — 7/8" Shaft Vertical Plunger, 3400 PSI 2.5 GPM, Front Inlet/Outlet

Biswing's replacement pressure washer pump is a 7/8" shaft vertical plunger unit rated to 3400 PSI and 2.5 GPM, designed to swap into compatible gas-powered washers for reliable cold-water cleaning performance.

This pump is built for homeowners and pros who need a direct-fit replacement for worn or failed pressure washer pumps. It uses a 7/8" shaft for horizontal engines, accepts a 3/4" NH garden hose inlet and an M22 high-pressure hose outlet, and operates up to 3400 PSI at 2.5 gallons per minute. The body is aluminum alloy for strength and heat dissipation, and a built-in thermal relief valve helps protect internal seals during demanding jobs. The package includes the pump, detergent hose, mounting hardware, shaft keys and nuts to simplify installation for many common gas units.

Will this Biswing pump fit my gas pressure washer engine?

Compatibility hinges on shaft size, engine orientation, and hose thread types. This model mounts to engines with a 7/8" shaft (horizontal engines) and pairs with standard 3/4" NH garden hose inlets and M22 high-pressure outlets, which are common on Simpson, Ryobi and many Honda-based units.

• 7/8" shaft — fits most 6.5–7 HP (180–225 cc) horizontal engines
• Front inlet/outlet layout — typical for many gas washers
• 3/4" NH inlet and M22 outlet — adapter may be needed for nonstandard hoses
• Cold-water use only — not for hot-water systems

How does the pump perform on heavy-duty cleaning tasks?

The Biswing unit delivers up to 3400 PSI and 2.5 GPM, balancing pressure and flow for removing dirt, mildew, oil stains and grime from concrete, decks, siding and vehicles when used correctly. The aluminum alloy body and robust plunger design maintain steady pressure under load while the thermal relief valve reduces the risk of heat damage during continuous operation.

• Max 3400 PSI for strong spray force
• 2.5 GPM for efficient rinsing and coverage
• Aluminum alloy construction for durability and heat dispersion
• Thermal relief valve helps protect seals under high temperature

What comes in the box and what additional parts might I need?

The pump ships with the basic hardware to replace most OEM pumps: bolts, locknuts, flat pads, shaft keys and a detergent pickup hose. Depending on your pressure washer’s hose fittings or manifold design you might need a coupler adapter, different hose threads or a new pump-to-engine gasket to complete the swap.

• Included: replacement pump, detergent hose, 3 M8 bolts, 3 M8 locknuts, 3 M8 flat pads, 2 shaft keys
• May need: inlet/outlet adapters or couplers for nonstandard hoses
• Check: compatibility with your engine’s shaft length and mounting holes
• Not included: oil (if required for some pump types) or specialized gaskets

How straightforward is installation and maintenance?

Installation is intended to be do-it-yourself friendly for those comfortable with basic mechanical tasks: mounting bolts, shaft keying and hose fittings are standard steps. Regular maintenance—keeping inlet filters clean, using cold water only and avoiding dry-run operation—extends pump life and preserves pressure performance.

• DIY install: bolt-on design with supplied hardware and shaft keys
• Simple hose connections: 3/4" NH inlet and M22 outlet (adapters available)
• Maintenance tips: keep inlet filter clean and avoid running dry
• Use cold water only; inspect seals and connections periodically

Who this is for: The Biswing 3400 PSI, 2.5 GPM 7/8" shaft pump suits homeowners, rental operators and light commercial users who need a cost-effective replacement for common gas-powered pressure washers. Choose this pump if your machine uses a horizontal 7/8" shaft, you require up to 3400 PSI for tough cleaning, and you want an aluminum-bodied unit with standard garden and high-pressure hose connections. If your washer is a hot-water model or uses a different shaft size, look for a pump matched to those specifications instead.