Description

The 4SPX32G1I is a high-quality, direct-drive plunger pump manufactured by Cat Pumps. Designed for the pressure washing industry, this “all-in-one” package is built to bolt directly onto a gasoline engine with a 1″ horizontal shaft.

The “UNL/INJ” designation indicates that this model comes pre-assembled with an integrated pressure unloader and a chemical injector, making it ready for immediate installation.

Technical Specifications

• Flow Rate: $3.2\ \text{GPM}$ (Gallons Per Minute).

• Max Pressure: $3000\ \text{PSI}$.

• RPM: $3450\ \text{RPM}$ (Matched for standard high-speed gas engines).

• Shaft Diameter: $1″$ (Hollow shaft).

• Inlet Port: $1/2″\ \text{NPT(F)}$.

• Discharge Port: $3/8″\ \text{NPT(M)}$.

• Material: Forged brass manifold with solid ceramic plungers.

Key Features

• Integrated Unloader: Automatically redirects water flow into bypass when the trigger gun is closed, preventing pressure spikes that could damage the pump or engine.

• Chemical Injector (INJ): Features a fixed downstream injector that allows you to draw detergents into the water stream (typically used with a low-pressure “soap” nozzle).

• Compact Footprint: The hollow-shaft design eliminates the need for bulky pulleys, belts, or gearboxes, reducing the overall size of the pressure washer.

• Triplex Design: Utilizes three ceramic plungers to provide a smoother, more consistent flow with less vibration than axial or duplex pumps.

Primary Application

• Commercial/Residential Pressure Washers: Specifically designed for engines in the 8HP to 11HP range (such as the Honda GX270 or GX340). It is a popular upgrade or replacement for worn-out pumps on professional-grade portable units.

Pro-Tips for Longevity

• Thermal Protection: If you are not using a bypass tank, do not leave the engine running with the trigger closed for more than 2 minutes. The water inside the head will heat up rapidly and can “cook” the seals.

• Pump Oil: Use Cat Pump ISO 68 non-detergent oil. Check the sight glass regularly; the oil should be clear. If it looks milky, water has bypassed the seals, and a service is required immediately.

• Inlet Filtration: Always use a water filter on the inlet. Even tiny grains of sand or “pipe scale” can score the ceramic plungers or pit the stainless steel valves at $3000\ \text{PSI}$.

• Gravity Feed vs. Pressure: While these pumps can “draw” water, they perform significantly better and last longer when supplied with pressurized water from a standard garden hose.