Marine Water Pump

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

Raw Water Intake: Seawater is drawn through an intake and filtered by a strainer.
Pump Operation: Gear-driven raw water pump sends water to the heat exchanger.
Heat Transfer: Seawater absorbs heat from internal coolant inside the exchanger.
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.