Cummins Marine Water Pumps (Raw Water Pumps)

Overview

Marine water pumps for Cummins engines are vital components of the engine’s cooling system. These pumps help draw seawater or raw water into the engine to control its operating temperature, ensuring reliable performance in harsh marine conditions. At Diesel Pro Power, we specialize in supplying high-quality aftermarket marine water pumps built to meet or exceed OEM standards for Cummins engine models used in commercial, recreational, and industrial marine applications.

With rapid 24-hour order processing, expert customer service, and an extensive in-stock catalog, we ensure fast, accurate delivery for fleets and operators who rely on dependable Cummins engines in their vessels.

Why Diesel Pro Power Is the Trusted Source for Marine Water Pumps (Raw Water Pump)

Fast Turnaround

We ship most orders within 24 hours. You’ll know exactly when your order ships and can track it with confidence.

Comprehensive Warranty

Every marine water pump and component sold through Diesel Pro Power is backed by a full warranty. Our aftermarket parts meet or exceed the durability and performance specs of the originals.

Dedicated Customer Support

Need help identifying the correct pump? Our knowledgeable team can guide you based on engine model, serial number, or application. Call us at 1-888-433-4735 (US) or 305-545-5588 (international).

User-Friendly Website

Our website is easy to use and includes detailed product descriptions, compatibility details, and customer support resources.

Understanding the Function of Marine Water Pumps (Raw Water Pump)

Marine water pumps are responsible for drawing seawater (often called raw water) into a Cummins marine engine to regulate temperature. This raw water is circulated through the engine’s heat exchanger, where it absorbs the engine’s excess heat. After passing through the cooling system, the now-heated seawater is expelled overboard, completing a continuous loop that prevents the engine from overheating.

This cooling method is essential for marine environments where engines often run under heavy loads for long periods. In commercial and industrial vessels, especially those powered by Cummins engines, operating temperatures must remain within optimal limits to ensure fuel efficiency, power output, and engine longevity. Even a slight variation in temperature can compromise performance or cause a complete shutdown.

Unlike closed-loop cooling systems found in vehicles, marine engines often depend on raw water pumps because of their ability to constantly pull in cool seawater from the surrounding environment. This is especially critical in warm coastal or tropical regions, where engine temperatures can spike rapidly if raw water flow is interrupted.

If the marine water pump fails—whether due to impeller damage, gasket failure, or corrosion—the engine will quickly overheat. In worst-case scenarios, this can lead to warped cylinder heads, cracked blocks, or complete engine failure. That’s why replacing marine water pumps, or maintaining them through repair kits and inspections, is a vital part of preventative maintenance for any Cummins-powered vessel.

Core Components of a Marine Water Pump

To function properly, marine water pumps rely on several internal components that each serve a specific role in keeping the cooling system running smoothly:

Impellers

Impellers are flexible, rubberized components with multiple blades (or vanes) that rotate inside the pump housing. As the impeller spins, it creates suction to draw in raw water and push it through the engine’s cooling passages. Over time, these vanes wear down or break off due to heat, friction, or debris in the water.

A damaged or worn impeller is one of the most common causes of pump failure. Regular inspection and seasonal replacement—especially in saltwater environments—are key to preventing overheating and maintaining proper water flow. Diesel Pro Power offers both individual impellers and full impeller kits for every supported Cummins model.

Gaskets

Gaskets form a watertight seal between the pump housing and the engine block. These flat, compressible components ensure that raw water or coolant does not leak from the connection point. If a gasket becomes brittle, cracked, or misaligned, it can lead to internal leaks that reduce cooling performance and potentially allow air to enter the system—causing cavitation and pump damage.

High-quality aftermarket gaskets, like those sold by Diesel Pro Power, are made of durable materials designed to withstand the high temperatures and corrosive effects of marine environments.

Zinc Anodes

Zinc anodes are essential sacrificial components that protect the marine water pump’s internal metal surfaces from galvanic corrosion. In saltwater conditions, different metals in contact with each other—like bronze housings and stainless-steel shafts—create a mild electric current. Without an anode, this reaction causes the metals in the pump to corrode over time.

Zinc anodes are installed in pump bodies or cooling passages to “sacrifice” themselves and absorb this corrosion instead. These must be replaced regularly to continue providing protection. Diesel Pro Power stocks zinc anodes for Cummins engines in various sizes and thread types to match every pump design.

Engine Compatibility: Marine Water Pumps by Cummins Model

Each Cummins engine model requires a specifically engineered pump. Below are the most common Cummins marine engine models supported by Diesel Pro Power's aftermarket pump inventory:

Marine Water Pumps For Cummins B Series – 4BTA, 6BT, 6BTA, QSB

Applications: Fishing vessels, small commercial boats, patrol boats

• 4BTA: A 3.9L turbocharged engine used in smaller vessels. The marine water pump is compact and optimized for fuel efficiency. 

• Raw Water Pump Catalog for Cummins 4BTA
  
  

  • Marine Water Pump for Cummins 4BTA

  • Marine Water Pump Impeller for Cummins 4BTA

  • Gasket to Mount the Marine Water Pump for Cummins 4BTA

  • Heat Exchanger - New for Cummins 4BTA

  • Impeller Puller for Marine Water Pumps for Cummins 4BTA

  • Zinc for Marine Engine - for Marine Water Pumps for Cummins 4BTA

  • Zinc for Cummins Marine Engine Fuel and Oil Coolers for Cummins 4BTA

  • Heat Exchanger O-Ring Gasket Seal for Cummins 4BTA

  • Intake Water Strainer for Cummins 4BTA

  • Coolant Hose, Silicone for Cummins 4BTA

  • Clamp for a Coolant and Fuel Hose for Cummins 4BTA

   

• 6BT: A 5.9L naturally aspirated version of the B Series, commonly found in older or simplified marine applications. Offers dependable power with fewer electronic controls. 

• Raw Water Pump Catalog for Cummins 6BT
  

  • Marine Water Pump for Cummins 6BT

  • Gasket to Mount the Marine Water Pump for Cummins 6BT

  • Impeller Puller for Marine Water Pumps for Cummins 6BT

  • Zinc for Marine Engine - for Marine Water Pumps for Cummins 6BT

  • Zinc for Cummins Marine Engine Fuel and Oil Coolers for Cummins 6BT

  • Heat Exchanger O-Ring Gasket Seal for Cummins 6BT

  • Intake Water Strainer for Cummins 6BT

  • Coolant Hose, Silicone for Cummins 6BT

  • Clamp for a Coolant and Fuel Hose for Cummins 6BT

  • Impeller for Key Shaft for Cummins 6BT

  • Marine Water Pump O-Ring for Cummins 6BT

  • Heat Exchanger Gasket Seal for Cummins 6BT

   

• 6BTA: A 5.9L inline 6-cylinder engine found in a wide range of commercial and recreational vessels. 

• Raw Water Pump Catalog for Cummins 6BTA
  

  • Marine Water Pump for Cummins 6BTA

  • Gasket to Mount the Marine Water Pump for Cummins 6BTA

  • Impeller Puller for Marine Water Pumps for Cummins 6BTA

  • Zinc for Marine Engine - for Marine Water Pumps for Cummins 6BTA

  • Zinc for Cummins Marine Engine Fuel and Oil Coolers for Cummins 6BTA

  • Heat Exchanger O-Ring Gasket Seal for Cummins 6BTA

  • Intake Water Strainer for Cummins 6BTA

  • Coolant Hose, Silicone for Cummins 6BTA

  • Clamp for a Coolant and Fuel Hose for Cummins 6BTA

  • Impeller for Key Shaft for Cummins 6BTA

  • Marine Water Pump O-Ring for Cummins 6BTA

  • Heat Exchanger Gasket Seal for Cummins 6BTA

   

• QSB: The electronic version of the B series with improved emissions and advanced fuel systems. Compatible pumps are often higher precision.

•  Raw Water Pump Catalog for Cummins QSB 5.9L
  

  • Marine Water Pump for Cummins QSB 5.9

  • Impeller for Splined Shaft (Marine Water Pump) for Cummins QSB 5.9

  • Impeller Puller for Marine Water Pumps for Cummins QSB 5.9

  • Zinc for Marine Engine - for Marine Water Pumps for Cummins QSB 5.9

  • Zinc for Cummins Marine Engine Fuel and Oil Coolers for Cummins QSB 5.9

  • Intake Water Strainer for Cummins QSB 5.9

  • Coolant Hose, Silicone for Cummins QSB 5.9

  • Clamp for a Coolant and Fuel Hose for Cummins QSB 5.9

  • Marine Water Pump O-Ring for Cummins QSB 5.9

   

•  Raw Water Pump Catalog for Cummins QSB 6.7L
  

  • Marine Water Pump for Cummins QSB 6.7

  • Gasket to Mount the Marine Water Pump for Cummins QSB 6.7

  • Impeller Puller for Marine Water Pumps for Cummins QSB 6.7

  • Zinc for Marine Engine - for Marine Water Pumps for Cummins QSB 6.7

  • Zinc for Cummins Marine Engine Fuel and Oil Coolers for Cummins QSB 6.7

  • Intake Water Strainer for Cummins QSB 6.7

  • Coolant Hose, Silicone for Cummins QSB 6.7

  • Clamp for a Coolant and Fuel Hose for Cummins QSB 6.7

  • Impeller for Splined Shaft for Cummins QSB 6.7

  • Marine Water Pump O-Ring for Cummins QSB 6.7

   

• Raw Water Pump Catalog for Cummins QSB 7.0L
  

  Marine Water Pump for Cummins QSB 7.0L

  Impeller Puller for Marine Water Pumps for Cummins QSB 7.0L

   

Marine Water Pumps For Cummins C Series – 6CTA, QSC

Applications: Ferries, large yachts, pilot boats

• 6CTA: A 8.3L inline 6 used extensively in commercial marine settings. 

• Raw Water Pump Catalog for Cummins 6CTA
  

  • Marine Water Pump for Cummins 6CTA

  • Gasket to Mount the Marine Water Pump for Cummins 6CTA

  • Impeller Puller for Marine Water Pumps for Cummins 6CTA

  • Zinc for Marine Engine – for Marine Water Pumps for Cummins 6CTA

  • Zinc for Cummins Marine Engine Fuel and Oil Coolers for Cummins 6CTA

  • Heat Exchanger (New) for Cummins 6CTA

  • Heat Exchanger Gasket Seal for Cummins 6CTA

  • Intake Water Strainer for Cummins 6CTA

  • Coolant Hose, Silicone for Cummins 6CTA

  • Clamp for a Coolant and Fuel Hose for Cummins 6CTA

  • Impeller for Key Shaft for Cummins 6CTA

  • Impeller for Splined Shaft for Cummins 6CTA

  • Marine Water Pump O-Ring for Cummins 6CTA

  • Thermostat for Cummins 6CTA

  • Hose, Plain for Cummins 6CTA

  • Hose, Elbow for Cummins 6CTA

   

• QSC: Offers electronic controls, quieter operation, and more efficient performance. 

• Raw Water Pump Catalog for  Cummins QSC
  

  • Marine Water Pump for Cummins QSC

  • Gasket to Mount the Marine Water Pump for Cummins QSC

  • Impeller Puller for Marine Water Pumps for Cummins QSC

  • Zinc for Marine Engine – for Marine Water Pumps for Cummins QSC

  • Zinc for Cummins Marine Engine Fuel and Oil Coolers for Cummins QSC

  • Intake Water Strainer for Cummins QSC

  • Coolant Hose, Silicone for Cummins QSC

  • Clamp for a Coolant and Fuel Hose for Cummins QSC

  • Impeller for Key Shaft for Cummins QSC

  • Marine Water Pump O-Ring for Cummins QSC

  • Thermostat for Cummins QSC

  • Heat Exchanger Gasket for Cummins QSC

   

Each model uses pumps with tailored flow rates, impeller configurations, and inlet/outlet orientations.

Marine Water Pumps For Cummins L Series –  QSL

Applications: Mid-size commercial vessels, workboats

• QSL: The Quantum series version with high-pressure common rail fuel systems. 

• Raw Water Pump Catalog for  Cummins QSL
  

  • Marine Water Pump for Cummins QSL

  • Gasket to Mount the Marine Water Pump for Cummins QSL

  • Impeller Puller for Marine Water Pumps for Cummins QSL

  • Zinc for Marine Engine – for Marine Water Pumps for Cummins QSL

  • Intake Water Strainer for Cummins QSL

  • Coolant Hose, Silicone for Cummins QSL

  • Clamp for a Coolant and Fuel Hose for Cummins QSL

  • Marine Water Pump Impeller for Cummins QSL

  • Marine Water Pump O-Ring for Cummins QSL

  • Thermostat for Cummins QSL

  • Heat Exchanger Gasket for Cummins QSL

   

Diesel Pro Power stocks marine water pumps engineered for both L series variants.

Marine Water Pumps For Cummins M Series – M11, ISM, QSM

Applications: Tugs, transport vessels, harbor service boats

• QSM: Electronic-controlled, high-power version with larger cooling demands. 

• Raw Water Pump Catalog for QSM11
  

  • Marine Water Pump for Cummins QSM11

  • Impeller Puller for Marine Water Pumps for Cummins QSM11

  • Zinc for Marine Engine – for Marine Water Pumps for Cummins QSM11

  • Intake Water Strainer for Cummins QSM11

  • Coolant Hose, Silicone for Cummins QSM11

  • Clamp for a Coolant and Fuel Hose for Cummins QSM11

  • Marine Water Pump Impeller for Cummins QSM11

  • Thermostat for Cummins QSM11

  • Thermostat Seal for Cummins QSM11

  • Zinc for Cummins Marine Engine Fuel and Oil Coolers for Cummins QSM11

   

Our pumps for these models are engineered for volume output and continuous duty cycles.

Marine Water Pumps For Cummins N Series – NT855

Applications: Ferries, dredgers, workboats

• NT855: A heavy-duty engine with a reputation for durability. Marine water pumps for this engine are large-capacity units with robust impellers and housings. 

• Raw Water Pump Catalog for  Cummins NT855
  

  • Marine Water Pump for Cummins NT855

  • Impeller Puller for Marine Water Pumps for Cummins NT855

  • Zinc for Marine Engine – for Marine Water Pumps for Cummins NT855

  • Intake Water Strainer for Cummins NT855

  • Coolant Hose, Silicone for Cummins NT855

  • Clamp for a Coolant and Fuel Hose for Cummins NT855

  • Marine Water Pump Impeller for Cummins NT855

  • Thermostat for Cummins NT855

  • Zinc for Cummins Marine Engine Fuel and Oil Coolers for Cummins NT855

   

Marine Water Pumps For Cummins K Series – KTA19, KTA38, KTA50

Applications: Offshore supply vessels, tugs, commercial trawlers

• KTA19: One of Cummins’ most iconic marine engines, often found on commercial vessels. 

• Raw Water Pump Catalog for Cummins KTA19
  

  • Marine Water Pump for Cummins KTA19

  • Impeller Puller for Marine Water Pumps for Cummins KTA19

  • Zinc for Marine Engine – for Marine Water Pumps for Cummins KTA19

  • Intake Water Strainer for Cummins KTA19

  • Coolant Hose, Silicone for Cummins KTA19

  • Clamp for a Coolant and Fuel Hose for Cummins KTA19

  • Marine Water Pump Impeller for Cummins KTA19

  • Thermostat for Cummins KTA19

  • Zinc for Cummins Marine Engine Fuel and Oil Coolers for Cummins KTA19

  • Thermostat Seal for Cummins KTA19

  • Thermostat Gasket for Cummins KTA19

   

• KTA38 & KTA50: Larger-displacement V12 and V16 engines with high-flow water pump requirements. 

• Raw Water Pump Catalog for Cummins  KTA38 
  

  • Marine Water Pump for Cummins KTA38

  • Thermostat for Cummins KTA38

  • Zinc for Marine Engine – for Marine Water Pumps for Cummins KTA38

  • Intake Water Strainer for Cummins KTA38

  • Coolant Hose, Silicone for Cummins KTA38

  • Clamp for a Coolant and Fuel Hose for Cummins KTA38

  • Impeller Puller for Marine Water Pumps for Cummins KTA38

  • Zinc for Cummins Marine Engine Fuel and Oil Coolers for Cummins KTA38

  • Thermostat Seal for Cummins KTA38

   

• Raw Water Pump Catalog for Cummins KTA50
  

  • Marine Water Pump for Cummins KTA50

  • Thermostat for Cummins KTA50

  • Zinc for Marine Engine – for Marine Water Pumps for Cummins KTA50

  • Intake Water Strainer for Cummins KTA50

  • Coolant Hose, Silicone for Cummins KTA50

  • Clamp for a Coolant and Fuel Hose for Cummins KTA50

  • Impeller Puller for Marine Water Pumps for Cummins KTA50

  • Zinc for Cummins Marine Engine Fuel and Oil Coolers for Cummins KTA50

  • Thermostat Seal for Cummins KTA50

   

We stock aftermarket marine water pumps designed to handle these engines' extreme duty cycles.

QSK Series – QSK19

Applications: High-speed ferries, large cargo support vessels

• QSK19: Advanced electronic and high-horsepower model with dual-circuit cooling. 

• Raw Water Pump Catalog for QSK19
  

  • Marine Water Pump for Cummins QSK19

  • Thermostat for Cummins QSK19

  • Zinc for Marine Engine – for Marine Water Pumps for Cummins QSK19

  • Intake Water Strainer for Cummins QSK19

  • Coolant Hose, Silicone for Cummins QSK19

  • Clamp for a Coolant and Fuel Hose for Cummins QSK19

  • Impeller Puller for Marine Water Pumps for Cummins QSK19

  • Zinc for Cummins Marine Engine Fuel and Oil Coolers for Cummins QSK19

  • Thermostat Seal for Cummins QSK19

  • Marine Water Pump Impeller for Cummins QSK19

   

Water pumps for QSK engines are high-capacity, precision-built components available through Diesel Pro Power.

Signs Your Cummins Marine Water Pump Needs Replacement

• Engine overheating or inconsistent temperatures

• Visible coolant or seawater leaks

• Corroded zincs or failed gaskets

• Worn, cracked, or missing impeller vanes

• Reduced seawater flow through the exhaust

Regular inspection and proactive replacement can avoid costly downtime or engine failure.

How to Select the Right Marine Water Pump

To ensure you receive the correct marine water pump, you’ll need:

• Engine model and serial number or CPL number (especially for electronic engines)

• Mounting orientation and inlet/outlet specs

• Compare your pump with the pictures on our sites and the dimensions in the description. 

Need help identifying these? Call our expert team and we’ll guide you.

Raw Water Pump Repair Kits for Cummins Engines

In addition to complete marine water pumps, Diesel Pro Power also offers raw water pump repair kits for many Cummins marine engine models. These kits are ideal for customers looking to rebuild their existing pump housings without replacing the entire unit.

Each kit may include:

• Replacement impeller

• Gasket(s)

• O-rings

• Seals and wear plates

• Shaft bearings (depending on model)

Using a raw water pump repair kit is a cost-effective solution for routine service or when you notice wear in internal components but the pump body remains structurally sound. Rebuilding your pump using OEM-equivalent aftermarket parts can restore cooling performance and extend the life of your Cummins marine engine.

Shipping, Payment & Warranty Info

• Worldwide shipping available with fast delivery to most marine ports

• Multiple payment options, including wire transfers and credit cards

• Encrypted transactions for security

• Full product warranty on every item

Frequently Asked Questions – Raw Water Pumps for Cummins Marine Engines

1. What does a raw water pump do on a Cummins 6CTA marine engine?
   A raw water pump on a 6CTA marine engine pulls seawater into the cooling circuit to regulate engine temperature. To find the right replacement, go to our website, select the 6CTA model, and compare the product photo and dimensions to your current pump.

2. How often should I replace the raw water pump impeller on a Cummins 6BTA engine?
   Impellers on 6BTA engines should be replaced annually or every 100 hours of use. The quickest way to confirm fitment is to match the photo and specs on our 6BTA product page with your existing pump.

3. Do you sell raw water pump repair kits for the Cummins QSM11?
   Yes. We offer repair kits for QSM11 engines that include impellers, seals, and gaskets. Use our QSM11 section to visually confirm the kit matches your existing pump.

4. Can I rebuild the raw water pump on a Cummins KTA19 instead of replacing it?
   Absolutely. If the pump housing is in good condition, our KTA19 repair kits can restore performance. Just compare the kit image and description to your current setup.

5. Are raw water pumps for Cummins QSB 6.7 and QSB 5.9 the same?
   Not always. Each QSB variant may use a different pump. Identify the correct one by visiting our QSB page and comparing the part’s photo and measurements.

6. What are signs the raw water pump is failing on a Cummins QSM11 engine?
   Typical signs include engine overheating, leaks, or reduced water flow. Go to our QSM11 product page and visually compare the pump to yours for a replacement.

7. How do I identify the correct raw water pump for my Cummins NT855 engine?
   While the serial number can help, the easiest method is to visit our NT855 page, select the pump, and compare its image and measurements to your current one.

8. Is the raw water pump for a Cummins QSK19 designed for dual-circuit cooling systems?
   Yes, many QSK19 applications use dual-circuit cooling. Visit our QSK19 catalog and verify the pump by comparing photos, ports, and size to your original part.

9. Can I upgrade the raw water pump on my Cummins 4BTA to improve performance?
   Upgrades are limited, but a higher-quality aftermarket pump from our 4BTA section with improved materials may increase reliability. Match your pump visually on our site.

10. Do you carry raw water pumps for the Cummins KTA38 marine engine?
    Yes, Diesel Pro Power stocks raw water pumps for the KTA38. Simply visit our KTA38 catalog page and compare the photos and specs to your current pump for confirmation.

11. What causes raw water pump failures on Cummins 6BTA engines?
    Common causes include worn impellers, clogged inlets, or deteriorated zincs. You can find compatible replacements by matching your pump visually on our 6BTA page.

12. Can I use the same raw water pump for both 6CTA and QSC Cummins engines?
    No. Despite both being part of the C Series, their cooling systems differ. Visit our QSC catalog and compare your existing pump’s design to our listing.

13. Do KTA38 and KTA50 Cummins engines use the same raw water pump?
    Yes, the KTA38 and KTA50 share the same pump. Visit our site, select your engine model, and compare the listing photo and measurements to your pump to confirm.

14. What is included in a raw water pump rebuild kit for Cummins engines?
    Our rebuild kits typically include an impeller, seals, O-rings, and mounting gaskets. Use the product images on our website to ensure you're selecting the correct kit for your engine.

15. What’s included in a Cummins 6CTA raw water pump repair kit?
    Kits usually include an impeller, seals, gasket, and hardware. You can confirm compatibility by visually matching the kit contents on our 6CTA page to your pump.

16. Can I order raw water pumps for Cummins marine engines internationally?
    Yes. Diesel Pro Power ships worldwide. Simply choose your engine model on our website and compare the pump image and dimensions to your current setup.

17. How do I check if my QSK19 raw water pump is working properly?
    Look for strong water discharge from the exhaust and stable engine temps. If performance drops, visit our QSK19 section and match the pump by photo and measurements.

18. Do Cummins 4BTA and 6BT use the same raw water pump?
    Not always. Differences in housing or orientation may apply. Visit our catalog and select your engine model to visually confirm the correct pump.

19. Are raw water pumps for Cummins QSL engines compatible with electronic controls?
    Yes. Newer QSL pumps are designed to integrate with ECMs. Confirm compatibility by comparing your pump’s image and specs on our QSL product page.

20. Do you offer raw water pump diagrams or install guides for the Cummins KTA19?
    Yes. Diagrams and helpful resources are available upon request. Start by finding your matching pump on our KTA19 catalog and comparing the layout to your own.

21. Are your marine raw water pumps for Cummins engines in stock?
    Yes. All of our raw water pumps for Cummins marine engines are in stock and ready to ship within 24 hours, ensuring fast delivery to your location.

22. How often should I change the raw water pump on my Cummins engine?
    While pumps last several years, it’s a best practice to inspect annually and replace the complete pump or use a rebuild kit every 2–3 years depending on use and environment.

23. Do your raw water pump kits include mounting hardware?
    Yes, most of our kits include necessary seals, O-rings, and gaskets. Some models also include bolts or washers. Always check the product description and compare to your pump.

24. Do I need a serial number to find the right pump?
    While helpful, a serial number is not required. The fastest way is to select your Cummins engine model on our website and compare the listing’s picture and measurements to your existing pump.

25. Can I get help selecting a raw water pump if I’m unsure of my engine model?
    Yes. Contact our support team with a clear photo of your pump and any markings on the housing. We’ll help you match it quickly using our in-stock inventory.