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Product / / 85.119.030B

CAT 4DNX27GS1 Pump – 2.7 GPM, 3,000 PSI, 3/4" Shaft

CAT 4DNX27GS1 Pump – 2.7 GPM, 3,000 PSI, 3/4" Shaft

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Specifications

UNLOADER

Built-In

WARRANTY

5 Years

RPM

3,450

PUMP MODEL

CAT 4DNX27GSI

PUMP TYPE

Triplex

Oil Type

30W Non Detergent

Oil Capacity

8.5 oz

Thermal Relief Value

85.300.022

Max Inlet Temperature

60°C / 140°F

Manifold Type

Brass

Soap Injector

Fixed

Inlet Size

3/4" GHF

Plunger Piston

Ceramic

Unloader Type

Built-In

Max GPM

2.7

Shaft Size

3/4"

Direct Drive

Gas

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PRODUCT

DESCRIPTION

Professional Triplex Pump for Reliable Pressure Washer Performance

The CAT 4DNX27GS1 Pump (Bare Pump Part #85.110.030) is a high-performance triplex direct-drive gas pump engineered for durability, precision, and efficiency. Delivering up to 3,000 PSI at 2.7 GPM, this pump is designed for contractors, commercial operators, and dedicated homeowners who demand professional-grade cleaning power.

Built by CAT Pumps, one of the most trusted names in the pressure washer industry, the 4DNX27GS1 features ceramic plungers, a brass manifold, and a built-in unloader for extended service life and consistent results. Packaged boxed and backed by CAT’s 5-year warranty, this pump is a long-term solution for restoring or upgrading your gas-powered pressure washer.

Key Features

  • Bare Pump Part #: 85.110.030

  • Pump Manufacturer: CAT

  • Pump Model: 4DNX27GS1

  • Pump Style: Triplex, direct-drive gas

  • Max PSI: 3,000

  • Max GPM: 2.7

  • Shaft Size: 3/4"

  • Unloader Type: Built-in

  • Plunger (Piston): Ceramic for maximum durability

  • Inlet Size: 3/4" GHF (garden hose fitting)

  • Discharge Size: 3/8" Brass QC (85.300.103)

  • Soap Injector: Fixed, integrated for detergent application

  • Manifold Type: Brass for long-lasting strength

  • RPM: 3,450

  • Max Inlet Temp: 60°C / 140°F

  • Thermal Relief Valve: 85.300.022 included

  • Oil Capacity: 8.5 oz

  • Oil Type: 30W non-detergent oil

  • Weight: 11 lbs

  • Warranty: 5 Years

Engineered for Professional Power

The 4DNX27GS1 is designed with CAT’s legendary triplex plunger system, which uses three precision ceramic plungers to deliver smoother performance, higher efficiency, and longer service life compared to axial cam pumps. This design reduces vibration, improves sealing, and ensures consistent pressure delivery.

With a maximum output of 3,000 PSI at 2.7 GPM, this pump has the right combination of power and flow for tough cleaning jobs. From removing oil stains on concrete to cleaning fleet vehicles and heavy equipment, the 4DNX27GS1 provides the professional-level results that CAT pumps are known for.

The ceramic plungers resist heat and wear for maximum longevity, while the brass manifold delivers strength and corrosion resistance, even in demanding environments.

Convenience and Built-In Features

The pump includes a built-in unloader, simplifying installation and operation while ensuring smooth pressure regulation. This eliminates the need for additional external unloaders, reducing setup complexity.

A fixed soap injector is integrated for detergent application, making it easy to apply cleaning chemicals when using low-pressure nozzles. This function enhances versatility for jobs that require soap or degreasers.

The brass quick-connect discharge fitting (3/8”) provides secure, reliable connections to hoses and accessories, minimizing leaks and ensuring quick setup.

Protection and Maintenance

The 4DNX27GS1 is built with protective features to help extend its lifespan. It comes with a thermal relief valve (85.300.022) that automatically releases overheated water during extended bypass operation, preventing damage to seals and components.

The pump requires 8.5 oz of 30W non-detergent oil to keep moving parts properly lubricated. Routine oil checks and changes are simple and cost-effective, ensuring long-term reliability.

With a maximum inlet temperature of 140°F (60°C), the pump can handle higher water input temperatures than many comparable models, providing added flexibility for different job site conditions.

At 11 lbs, the pump is built to be rugged yet manageable for installation and maintenance.

Common Applications

The CAT 4DNX27GS1 Pump is a versatile, professional-grade solution for a variety of pressure washer applications. Its high PSI rating and triplex design make it suitable for both residential power users and commercial operators. Typical uses include:

  • Concrete and Driveway Cleaning – Blast away oil stains, dirt, and grime.

  • Fleet and Vehicle Washing – Clean cars, trucks, trailers, and RVs.

  • Agricultural Equipment – Maintain tractors, tools, and farm machinery.

  • Construction Sites – Wash down heavy equipment and prep surfaces.

  • Property Maintenance – Restore siding, brick, and outdoor furniture.

Its 3/4” shaft size ensures compatibility with many popular gas-powered engines, making it an ideal replacement pump for higher-end residential and commercial-grade washers.

Product Specifications

  • Part #: 85.110.030

  • Manufacturer: CAT

  • Model: 4DNX27GS1

  • Style: Triplex, direct-drive gas

  • Max Pressure: 3,000 PSI

  • Max Flow Rate: 2.7 GPM

  • Shaft Size: 3/4”

  • RPM: 3,450

  • Unloader: Built-in

  • Soap Injector: Fixed

  • Manifold Material: Brass

  • Plunger Material: Ceramic

  • Inlet Connection: 3/4” GHF

  • Discharge Connection: Brass QC 3/8" (85.300.103)

  • Oil Capacity: 8.5 oz (30W non-detergent oil)

  • Thermal Relief Valve: 85.300.022

  • Max Inlet Temp: 60°C / 140°F

  • Weight: 11 lbs

  • Warranty: 5 Years

Backed by CAT Pumps’ Reputation

For decades, CAT Pumps has been the industry standard for durability, precision, and long service life. The 4DNX27GS1 Pump continues this tradition, offering a triplex design, ceramic plungers, and brass manifold for professional-grade reliability.

Backed by a 5-year warranty, this pump provides exceptional long-term value and peace of mind, making it a top choice for contractors and homeowners alike.

When you need dependable cleaning power and unmatched durability, the CAT 4DNX27GS1 Pump is the professional’s choice—engineered for performance, built to last.

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Compare the specifications of your chosen pressure washers to determine the right fit for your application.

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85.119.030B
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Pump Model
CAT 4DNX27GSI - -
Pump Type
Triplex - -
Unloader
Built-In - -
Warranty
5 Years - -
RPM
3,450 - -

Frequently Asked Questions about Pressure Washers

How to store a pressure washer?

To ensure the durability of your heavy duty pressure washer:

  • Empty the gas tank to prevent fuel from degrading or clogging the engine.
  • Empty the pump and hoses of any remaining water.
  • Perform necessary maintenance before storage.
  • Store in a dry area.
  • Cover.

What is a pressure washer?

A power washer is a cleaning machine that uses a gasoline engine to power a high pressure water pump and nozzle. It’s used to clean driveways, decks, vehicles, outdoor furniture and more by spraying water at high PSI to remove dirt, grime, mold and other debris.Many models also come with a detergent tank for added cleaning power.

How does a power washer work?

A power washer works by drawing water from a connected hose and pumping it through a high pressure nozzle. The gas engine powers the pump which pressurizes the water and then expels it through the nozzle at high speed to clean the surface. The water pressure is measured in PSI (pounds per square inch) and the flow rate is measured in GPM (gallons per minute).Many models also feature adjustable water pressure settings to cater to different cleaning needs. BE makes pressure washing easy with models available for light jobs and heavy duty commercial cleaning projects.

Gas vs Electric power washers?

The main difference is that a gas pressure washer, known for its cleaning power, is powered by a gasoline engine, making it more powerful and portable, while an electric pressure washer is powered by electricity and is generally quieter and lighter.

Gas pressure washers are for heavy duty and large areas due to their durability, whereas electric pressure washers are for smaller jobs.

Your BE electric pressure washer is perfect for smaller jobs and built for portability, and we offer a wide range of electric models. Included with our electric models is a long extension cord for use anywhere around your house.

What to consider?

When choosing a gas pressure washer consider:

  • Pressure (PSI): More PSI means more cleaning power but also more potential for damaging delicate surfaces.
  • Flow Rate (GPM): More GPM means faster cleaning as more water is dispensed.
  • Engine Power: Bigger engines mean more durability and power.
  • Portability: Weight, handle design and wheel size for easier to move.
  • Nozzles: Multiple spray nozzles to adjust the spray pattern for different tasks.
  • Adjustable Nozzle: Allows for fine-tuning the spray intensity and pattern for various cleaning needs.

How much pressure do I need for?

The required pressure (PSI) and cleaning power depend on the surface you’re cleaning:

  • Light duty (car washing, outdoor furniture): 1,300-1,800 PSI.
  • Medium duty (patios, fences, decks): 2,000-3,000 PSI.
  • Heavy duty (driveways, brick walls, large equipment): 3,000+ PSI.

Many pressure washers come with adjustable pressure settings to handle different cleaning tasks effectively.

Can a pressure washing damage surfaces?

Yes, a power washer can damage surfaces if used incorrectly. High pressure water can strip paint, dent soft surfaces or even cause structural damage if the pressure is too high or the nozzle is held too close to the surface. Always use the right PSI for the material you’re cleaning and keep a safe distance from delicate surfaces.

To prevent damage, consider using a model with adjustable pressure settings.

How to maintain your pressure washer?

To ensure the durability and smooth operation of a pressure washer:

  • Change the oil as per manufacturer’s instructions.
  • Clean or replace the air filter to ensure good airflow.
  • Inspect and clean the nozzle regularly to prevent clogs.
  • Drain the gas tank if you’re storing the washer for a long time.
  • Check the hoses for leaks or damage and replace them if needed.
  • Follow regular maintenance requirements to keep the washer in optimal condition.

Can I use a pressure washer in cold weather and low water temperature?

You can use a pressure washer in cold weather but it’s more difficult. The water flow rate in the hoses and pump can freeze and damage the equipment. If you plan to use your pressure washer in cold temperatures make sure to winterize it and store it in a warm area when not in use. You can also use anti-freeze solutions for pressure washers.

Some models are designed to use hot water, which can be particularly effective for cleaning in cold weather.

Do I need any accessories?

Common accessories for power washers: