Kubota-Powered Performance

WATERAX diesel pumps combine proven pump technology with the reliable Kubota D902-E4B engine for demanding vehicle-mounted applications. The liquid-cooled 3-cylinder diesel delivers 24.8 HP with exceptional fuel efficiency and the durability apparatus builders trust.

Two pump series are available: the BB-4-D902 delivers high-pressure performance up to 395 PSI for long hose lays and high-elevation firefighting, while the B2X-D902 provides high-volume output up to 310 GPM for wildland-urban interface operations and rapid water transfer.

Both series feature the WATERAX quick-release clamp system, maintenance-free sealed bearings, and 14-pin FastWire connectivity for seamless integration with control panels. EPA, CARB, and CE emissions certified.

  • Superior Fuel Efficiency

    Diesel engines consume 30-40% less fuel than gasoline equivalents at comparable power output. Lower operating costs over the life of your apparatus.

  • Fleet Fuel Compatibility

    Run the same ultra-low sulfur diesel as your apparatus chassis. Simplify logistics with single-fuel operations and eliminate gasoline storage requirements.

  • Liquid-Cooled Durability

    The Kubota D902's liquid cooling system maintains optimal operating temperature during extended pumping operations that would overheat air-cooled engines.

  • Reduced Maintenance

    No spark plugs, no carburetor, no ignition timing issues. Fuel injection provides reliable cold starts and consistent performance in all conditions.

Choose Your Diesel Pump Series

Both diesel series share the same Kubota D902-E4B engine but pair it with different pump ends for distinct performance characteristics.

  • BB-4-D902 Performance

    Maximum Pressure: 395 PSI (27.2 BAR)
    Maximum Flow: 106 GPM (401 L/min)
    Maximum Head: 911 ft (278 m)
    Pump Type: 4-stage centrifugal
    Max Allowable: 600 PSI (41.4 BAR)

  • BB-4-D902 Flow at Pressure

    At 150 PSI: 103 GPM (390 L/min)
    At 250 PSI: 95 GPM (360 L/min)
    At 350 PSI: 55 GPM (208 L/min)

  • BB-4-D902 Best For

    Long hose lays, high-elevation firefighting, tandem pumping, parallel pumping, direct attack, sprinkler systems, Type 6 brush trucks. USFS Type 6 Fire Apparatus listed.

    Shop BB-4 Diesel 
  • B2X-D902 Performance

    Maximum Pressure: 180 PSI (12.4 BAR)
    Maximum Flow: 310 GPM (1173 L/min)
    Maximum Head: 415 ft (127 m)
    Pump Type: 2-stage centrifugal
    Max Allowable: 400 PSI (27.6 BAR)

  • B2X-D902 Flow at Pressure

    At 50 PSI: 274 GPM (1037 L/min)
    At 100 PSI: 220 GPM (833 L/min)
    At 150 PSI: 112 GPM (424 L/min)

  • B2X-D902 Best For

    Wildland-urban interface, dual attack lines, booster reels, high-volume water transfer, tank filling, structure protection. Ideal for initial attack units and brush trucks.

    Shop B2X Diesel 

Kubota D902-E4B Engine

Both diesel pump series are powered by the same proven Kubota engine.

  • Power Output

    Net Power: 24.8 HP (18.5 kW) @ 3600 RPM
    Net Torque: 40.6 lb-ft (55 Nm) @ 2600 RPM
    Idle Speed: 900-1000 RPM
    Compression Ratio: 24:1

  • Engine Design

    Configuration: 3-cylinder inline
    Displacement: 54.8 cu in (898 cc)
    Bore x Stroke: 2.83" x 2.9" (72 x 73.6 mm)
    Fuel Injection: Direct injection
    Aspiration: Naturally aspirated

  • Systems & Capacity

    Cooling: Liquid cooled
    Starting: 12 VDC, 1.0 kW with glow plug
    Charging: 12V, 40 Amp alternator
    Oil Capacity: 3.9 quarts (3.7 L)
    Fuel: Ultra Low Sulfur Diesel (≤15 ppm)

Pump End Specifications

Key differences between the BB-4 (high-pressure) and B2X (high-volume) pump ends.

  • BB-4 Pump End (4-Stage)

    Intake: 2" Male NPSH
    Discharge: 1-1/2" Male NPSH
    Priming Port: 1-1/2" Male NPSH
    Impellers: 3.67" diameter
    Max Allowable: 600 PSI
    Pump End: Identical to MARK-3

  • B2X Pump End (2-Stage)

    Intake: 3" NPT / 4" Victaulic
    Discharge: 2-1/2" NPT / 3" Victaulic
    Impellers: 4.00" diameter
    Max Allowable: 400 PSI
    Pump End: Swappable with B2X gas models

  • Common Features

    Construction: Anodized corrosion-resistant aluminum
    Shaft: Stainless steel
    Bearings: Maintenance-free sealed
    Seal: Blister-resistant carbon/silicon carbide
    Clamp: Hand-tight quick-release
    FastWire: 14-pin connector

Applications

WATERAX diesel pumps are designed for professional vehicle-mounted applications.

  • Type 6 Brush Trucks

    The BB-4-D902 is USFS Type 6 Fire Apparatus listed. Compatible with Type 4, 5, and 6 specifications. Diesel fuel matches chassis requirements for single-fuel operations.

  • Wildland-Urban Interface

    The B2X-D902 delivers 310 GPM for high-volume operations. Run dual 1-1/2" attack lines, supply 2-1/2" handlines, or fill tanks rapidly during WUI incidents.

  • Slip-On Units

    Both diesel series are popular choices for slip-on/skid-unit applications. Vehicle mounting with 4-leg frame design and FastWire for clean control panel integration.

  • OEM Apparatus Builds

    Designed for professional apparatus builders. Horizontal or vertical drive options, multiple control panel configurations, and comprehensive documentation for integration.

  • BB-4-D902 Data Sheet

    Official specifications, performance curves, and technical drawings for the BB-4 diesel high-pressure pump.

    Download PDF →

  • B2X-D902 Data Sheet

    Official specifications, performance curves, and technical drawings for the B2X diesel mid-range pump.

    Download PDF →

  • BB-4-D902 Owner's Manual

    Complete operating instructions, maintenance procedures, and safety guidelines for BB-4 diesel pumps.

    Download PDF →

  • D902 Engine Manual

    Kubota D902 engine service manual with maintenance schedules and troubleshooting.

    Download PDF →

Diesel vs. Gasoline Pumps

Both BB-4 and B2X series are also available with gasoline engines. Here's how to choose.

  • Choose Diesel When...

    • Fleet runs on diesel (single-fuel logistics)
    • Extended run times are common
    • Fuel efficiency is a priority
    • Operating in extreme heat conditions
    • You want to eliminate spark plug/carburetor maintenance
    • Building to USFS Type 6 specifications

  • Choose Gasoline When...

    • Weight is critical (diesel pumps are 280 lbs)
    • Initial cost is the primary concern
    • Portable configurations are needed
    • Lower-volume applications suffice
    • Existing fleet uses gasoline equipment
    • Cold-weather starting without glow plugs preferred

    View Gas Pumps 

Shop Diesel Pumps

  • BB-4-D902V

    High-pressure 4-stage with vertical drive. 395 PSI / 106 GPM. 14-pin FastWire, 4-leg vehicle mount. 280 lbs. USFS Type 6 listed.

    View BB-4-D902V 
  • BB-4-D902H

    High-pressure 4-stage with horizontal drive. 395 PSI / 106 GPM. 14-pin FastWire, 4-leg vehicle mount. 280 lbs. USFS Type 6 listed.

    View BB-4-D902H 
  • B2X-D902V

    High-volume 2-stage with vertical drive. 180 PSI / 310 GPM. 3" NPT/4" Vic intake, 2-1/2" NPT/3" Vic discharge. 280 lbs.

    View B2X-D902V 
  • B2X-D902H

    High-volume 2-stage with horizontal drive. 180 PSI / 310 GPM. 3" NPT/4" Vic intake, 2-1/2" NPT/3" Vic discharge. 280 lbs.

    View B2X-D902H 

Need Help Selecting a Diesel Pump?

Whether you're building a Type 6 brush truck, outfitting a slip-on unit, or specifying pumps for apparatus manufacturing, we can help you choose the right WATERAX diesel configuration for your application.