RKV4G37-PKG

Introduction: DIY Power, Professional Results
Building your own pressure washer system gives you flexibility, cost savings, and the ability to customize equipment for your needs. At the heart of any washer is the pump, and for those looking to achieve commercial performance, the Annovi Reverberi RKV4G37-PKG pump package is a top-tier choice. Delivering 4.0 GPM at 3700 PSI, this kit allows contractors, property managers, and serious DIYers to assemble a machine that rivals factory-built models.
When paired with a Predator 420cc engine from Harbor Freight or a Honda GX390, the RKV4G37-PKG becomes the foundation for a durable, versatile washer capable of tackling heavy-duty jobs in construction, agriculture, fleet washing, and municipal maintenance.

Why Choose the RKV4G37-PKG?
The RKV4G37-PKG stands apart from consumer-level pumps and offers a professional-grade foundation for a wide range of builds.

• Balanced Performance – 4.0 GPM provides strong rinsing power, while 3700 PSI delivers cutting pressure to tackle stubborn grime.
• Engine Ready – Equipped with a 1” hollow shaft and F24 gas engine flange for direct compatibility with popular horizontal-shaft engines.
• Pre-Boxed Kit – Comes complete with a VR35 unloader, thermal relief valve, garden hose adapter, and quick connect plug. No extra shopping for essential components.
• Durable Construction – Built with AR’s nickel-plated brass pump head, high-strength connecting rods, and oversized bearings for long-lasting reliability.
• Rebuildable – Unlike consumer axial pumps, the RKV is a triplex plunger pump designed for serviceability and years of continuous use.

This blend of durability, ease of installation, and included accessories makes the RKV4G37-PKG a ready-to-build solution for professionals and DIY enthusiasts alike.

Predator Engine Pairing
The Predator 420cc engine is a perfect match for the RKV4G37-PKG. At approximately 13 HP, it delivers steady torque and RPM, making it powerful enough to handle 3700 PSI without straining.
Advantages of Predator + RKV pairing:

• Widespread Availability – Harbor Freight offers Predator engines nationwide.
• Direct Compatibility – The RKV’s 1” hollow shaft bolts seamlessly to the Predator’s crankshaft.
• Proven Performance – 420cc output provides consistent horsepower for extended runtimes.
• Budget-Friendly Builds – Allows contractors to build commercial-level systems without premium engine price tags.

Other compatible engines include the Honda GX390, Briggs & Stratton, Kohler SH series, and other 13–15 HP horizontals, giving builders flexibility depending on preference and budget.

Key Applications
The RKV4G37-PKG’s output of 4.0 GPM @ 3700 PSI makes it an extremely versatile pump for demanding environments.

• Fleet Maintenance – Wash trucks, buses, and rental vehicles efficiently.
• Agriculture – Clean tractors, dairy equipment, and livestock facilities.
• Construction – Remove concrete residue, mud, and grease from heavy machinery.
• Municipal Services – Handle graffiti removal, sidewalks, public park sanitation, and street cleaning.
• Industrial – Degreasing shop floors, prepping steel surfaces, or washing equipment in plants.
• Contractor Use – Power for driveway cleaning, parking lot maintenance, and surface cleaner applications.

This versatility makes the RKV4G37-PKG a “workhorse pump package” suitable for a broad customer base.

What’s Included in the Pump Package?
The RKV4G37-PKG is more than just a pump—it’s a complete installation kit.

• Pump: RKV4G37DF24VR35 (4.0 GPM, 3700 PSI, 1” hollow shaft, F24 gas engine flange)
• VR35 Unloader: Protects pump by regulating system pressure.
• Thermal Relief Valve (TPP140): Prevents overheating during bypass cycles.
• Garden Hose Adapter (AR1264750): Makes water supply connection fast and reliable.
• Quick Coupling Plug (3/8”): Ensures easy high-pressure hose hookup.

With these components pre-packaged, setup is streamlined—no need to chase down parts or worry about compatibility.

Step-by-Step: Building Your Washer
Pairing the RKV4G37-PKG with a Predator or Honda engine is straightforward:

1. Mount the Pump – Slide the hollow shaft onto the engine crankshaft and secure it to the F24 flange.
2. Install Accessories – Attach the VR35 unloader, thermal relief valve, and quick coupler.
3. Hook Up Water Supply – Use the included adapter to connect a garden hose or tank feed.
4. Frame Mounting – Position the pump and engine on a skid, cart, or trailer frame for stability.
5. Test & Run – Fill with pump oil, start the engine, and you’re ready for 3700 PSI professional cleaning power.

This simple build process is why the RKV package line is popular with contractors who want both performance and control over their setup.

Why 3700 PSI at 4.0 GPM Hits the Sweet Spot

• Powerful Enough – Cuts through grease, oil, mildew, and grime quickly.
• High Flow – Rinses debris efficiently, perfect for surface cleaners and large flatwork.
• Safe Versatility – Aggressive pressure but not so extreme that it risks unnecessary surface damage.
• Efficient Cleaning – Balances pressure and water volume to reduce job time.

For most contractors and advanced homeowners, this flow/pressure combination provides the best all-around performance for diverse applications.

Long-Term Durability & Maintenance
The RKV series is designed for long life under heavy workloads:

• Nickel-Plated Brass Head – Corrosion-resistant for hot/cold water use.
• Triplex Design – Stainless plungers and replaceable seals for rebuildability.
• Oversized Bearings – Cooler operation, longer runtime, and extended service intervals.
• Comprehensive Parts Support – AR provides rebuild kits for valves, pistons, and seals, keeping downtime minimal.

Routine oil changes and O-ring replacements ensure this pump provides years of professional-grade service.

Key takeaway from the simplicity yet Efficiency of DIY a Pressure Washer System:

• RKV4G37 pump package
• Predator 420cc pressure washer build
• DIY 3700 PSI pressure washer kit
• Horizontal hollow shaft pressure washer pump
• VR35 unloader pump package
• Build your own commercial pressure washer
• Predator engine pressure washer compatibility

Conclusion: Professional Power, DIY Flexibility
The RKV4G37-PKG pump package gives contractors and serious users the ability to build a 3700 PSI, 4.0 GPM commercial-grade pressure washer tailored to their needs. With its direct compatibility with Predator and Honda engines, included unloader and safety components, and serviceable triplex design, this kit offers reliability and value far beyond consumer units.
Whether you’re cleaning fleets, prepping construction equipment, managing municipal services, or simply upgrading your shop rig, the RKV4G37-PKG provides the backbone for a professional, rebuildable, and high-performance washer.
 Build smarter. Save money. Unlock professional cleaning power with the RKV4G37-PKG + Predator 420cc combination.

For additional industry standards and technical resources, visit: https://www.pumps.org/

Why Choose the RKV4G37-PKG for Your Pressure Washer Project?