Cummins 4B Marine Raw Water Pump and Cooling System Parts Catalog

Maintaining a healthy cooling system is essential for any marine diesel engine, and the Cummins 4B is no exception. In this expanded catalog, we highlight every raw water pump component, accessory, and cooling system part needed to ensure your Cummins 4B engine stays cool and protected in harsh saltwater environments. Whether you're doing routine maintenance or overhauling a full system, Diesel Pro Power provides everything you need with same-day shipping and global support.

Complete Raw Water Pump for Cummins 4B

Gear-Driven Marine Water Pump

• Compatibility: Cummins 4B3.9 marine configurations
  
  

• Ports: 1 1/4" hose connection (inlet & outlet)
  
  

• Construction: Marine-grade bronze body with cast gear integration
  
  

• Performance: High-volume flow to maintain stable operating temperature in saltwater cooling circuits
  
  

The raw water pump is the central pumping mechanism that ensures seawater is effectively circulated through your heat exchanger system. Gear-driven for consistent power transfer and reduced maintenance.

Raw Water Pump Impeller

Flexible Neoprene Impeller

• Size: 2 9/16" diameter x 1 5/8" length
  
  

• Material: Flexible neoprene rubber
  
  

• Function: Rotating vanes pull seawater from intake into the cooling circuit
  
  

• Replacement Interval: Inspect every 100 hours; replace every 200 hours or annually
  
  

This impeller fits perfectly in the gear-driven water pump, offering dependable saltwater performance. Flexible design allows it to maintain a tight seal even in varied pressure conditions.

Gaskets and Seal Components

Marine Pump Mounting Gasket

• Provides a watertight seal between the pump and engine block or mounting bracket
  
  

• Precision-cut for Cummins marine engine geometry
  
  

Heat Exchanger O-Ring Gasket Seals

• Fitment: 4B, 4BT, 4BTA, 6B, 6BT, and 6BTA engines
  
  

• Quantity: 2 per engine required
  
  

• Prevents cross-contamination between coolant and seawater circuits
  
  

Heat Exchanger End Cap Gasket

• Size: 4” diameter
  
  

• Used to secure and seal end caps on marine heat exchangers
  
  

Cummins 4B Marine Heat Exchanger

New Heat Exchanger for Cummins 4B3.9

• Tube Material: Copper-nickel for superior heat transfer and saltwater corrosion resistance
  
  

• Body: Bronze casting for long service life
  
  

• Purpose: Transfers engine heat from internal coolant to raw seawater loop
  
  

This heat exchanger is purpose-built for marine duty cycles, enabling engine operation at optimal temperatures and protecting internal components from corrosion and thermal stress.

Zinc Anodes for Corrosion Protection

1/2" NPT Zinc

• Zinc Length: 2"
  
  

• Usage: Heat exchanger and aftercooler protection
  
  

• Function: Sacrificial metal absorbs corrosive energy and protects brass and copper parts
  
  

3/8" NPT Zinc for Fuel and Oil Coolers

• Zinc Length: 1"
  
  

• Provides corrosion resistance in compact cooler housings
  
  

Marine engines running in saltwater require frequent zinc inspection. Diesel Pro Power recommends monthly checks and replacement when zinc is more than 50% depleted.

Marine Intake Water Strainers

1" Pipe Size Strainer

• Dimensions: 9.5" height x 5.5" width
  
  

• Compact model for smaller boats or space-restricted installs
  
  

1.5" Pipe Size Strainer

• Dimensions: 11.5" height x 7.25" width
  
  

• More flow volume; suitable for moderate load marine engines
  
  

2" Pipe Size Strainer

• Dimensions: 16" height x 7.5" width
  
  

• High-capacity intake filtering for commercial use or twin-engine setups
  
  

2.5" Pipe Size Strainer

• Dimensions: 16" height x 7.5" width
  
  

• Heavy-duty design for continuous duty vessels and higher displacement engines
  
  

All strainers feature corrosion-proof housings, stainless steel baskets, and screw-top lids for quick cleaning.

Silicone Coolant Hoses (Per Foot)

Why Choose Silicone?

• Durability: Withstands salt, pressure, UV, and extreme heat
  
  

• Flexibility: Maintains form without cracking in tight engine bays
  
  

• Resistance: Excellent protection from chemical exposure and electrolysis
  
  

Available Sizes:

• 1"
  
  

• 1 3/4"
  
  

• 1 7/8"
  
  

• 2"
  
  

• 2 1/8"
  
  

• 2 1/4"
  
  

• 2 3/8"
  
  

• 2 1/2"
  
  

• 2 3/4"
  
  

• 3"
  
  

• 3 1/2"
  
  

• 4"
  
  

Each section sold by the foot. Stock multiple sizes to cover every run in your engine's seawater and coolant routing system.

Hose Clamps for Marine Environments

Stainless Steel Clamps

• Corrosion-Proof: Marine-grade stainless steel
  
  

• Secure Fit: Resists loosening under vibration
  
  

• Critical for: Preventing leaks and hose blowouts
  
  

Size Options:

• 9/16" – 1 1/16"
  
  

• 1" – 1.5"
  
  

• 13/16" – 1 3/4"
  
  

• 11/16" – 1 1/4"
  
  

• 1 5/16" – 2 1/4"
  
  

• 1 9/16" – 2 1/2"
  
  

• 2 5/16" – 3"
  
  

Clamps are easy to overlook during inspection, but often the cause of unexpected seawater leaks.

Impeller Puller Tool

Universal Impeller Puller

• Designed to remove impellers from marine raw water pumps without damaging the pump cavity or shaft
  
  

• Works on Cummins, Detroit Diesel, and most universal marine pump configurations
  
  

Ideal for onboard toolkits and marine technicians servicing impellers in confined engine rooms.

Cooling System Overview for Cummins 4B Marine Engines

1. Raw Water Intake: Seawater is drawn through an intake and filtered by a strainer.
   
   

2. Pump Operation: Gear-driven raw water pump sends water to the heat exchanger.
   
   

3. Heat Transfer: Seawater absorbs heat from internal coolant inside the exchanger.
   
   

4. Discharge: Heated seawater exits through the exhaust or overboard discharge port.
   
   

Each of these stages depends on healthy seals, effective pump performance, and secure hose routing.

Maintenance Tips

• Impeller: Check every 100 hours. Replace every 200 hours or once a year.
  
  

• Zinc Anodes: Inspect monthly. Replace when 50% depleted.
  
  

• Heat Exchanger: Flush once per season. Replace seals every 2 years.
  
  

• Hoses & Clamps: Check for swelling, softness, rust. Replace every 2–3 years.
  
  

Proactive maintenance on these components prevents breakdowns in open water and avoids expensive emergency repairs.

Why Diesel Pro Power?

• Over 40,000+ satisfied customers worldwide
  
  

• Exclusive supplier of high-quality parts for Cummins marine engines
  
  

• Same-day global shipping on all in-stock items
  
  

• Expert technical support from real diesel specialists
  
  

When you need reliability and fast delivery, Diesel Pro Power is your trusted source.