Water Pump Assembly – Fits Yanmar 6LY3 Series Marine Engines (Replaces 119578-42501)
Water Pump Assembly – Fits Yanmar 6LY3 Series Marine Engines (Replaces 119578-42501) is backordered and will ship as soon as it is back in stock.
Couldn't load pickup availability
Worry-free returns
Worry-free returns
You may return most new, unopened items within 7 days of delivery for a full refund. We'll also pay the return shipping costs if the return is a result of our error (you received an incorrect or defective item, etc.).
You should expect to receive your refund within four weeks of giving your package to the return shipper, however, in many cases you will receive a refund more quickly. This time period includes the transit time for us to receive your return from the shipper (5 to 10 business days), the time it takes us to process your return once we receive it (3 to 5 business days), and the time it takes your bank to process our refund request (5 to 10 business days).
If you need to return an item, simply login to your account, view the order using the "Complete Orders" link under the My Account menu and click the Return Item(s) button. We'll notify you via e-mail of your refund once we've received and processed the returned item.
Delivery and Shipping
Delivery and Shipping
Free standard shipping on all orders under 1 KG
Water Pump Assembly – Fits Yanmar 6LY3 Series Marine Engines (Repla...
Product Details
This is a direct replacement Water Pump Assembly – Fits Yanmar 6LY3 Series Marine Engines. It is designed for reliable raw water/sea water cooling performance in Yanmar 6LY3 series diesel engines, including the ETP, STP, UTP, STC, and UTC variants, as well as their 24V versions.
It is a direct interchange for Yanmar 119578-42501, Johnson 10-13286-01, and JMP Marine JPR-YM06LY3.
- Installation Method: Direct OEM replacement
- Housing Material: Bronze
- Connection Type: Hose
Part Number Matrix
Use this matrix to confirm equivalent references across OEM and aftermarket.
| Brand | Part Number |
|---|---|
| Yanmar | 119578-42501 |
| Johnson | 10-13286-01 |
| JMP Marine | JPR-YM06LY3 |
Engine & Model Compatibility
Confirm your engine model/year in the table below.
This pump is confirmed to fit the following Yanmar marine engines:
| Brand | Model | Stroke | OEM Part No. | Notes |
|---|---|---|---|---|
| Yanmar | 6LY3-ETP | 4-Stroke | 119578-42501 | |
| Yanmar | 6LY3-STP | 4-Stroke | 119578-42501 | |
| Yanmar | 6LY3-UTP | 4-Stroke | 119578-42501 | |
| Yanmar | 6LY3-STC | 4-Stroke | 119578-42501 | |
| Yanmar | 6LY3-UTC | 4-Stroke | 119578-42501 | |
| Yanmar | 6LY3-ETP 24 | 4-Stroke | 119578-42501 | 24V variant |
| Yanmar | 6LY3-STP 24 | 4-Stroke | 119578-42501 | 24V variant |
| Yanmar | 6LY3-UTP 24 | 4-Stroke | 119578-42501 | 24V variant |
| Yanmar | 6LY3-STC 24 | 4-Stroke | 119578-42501 | 24V variant |
| Yanmar | 6LY3-UTC 24 | 4-Stroke | 119578-42501 | 24V variant |
Technical Specs
- Product Type
- Sea Water / Raw Water Cooling Pump
- Installation
- Direct OEM replacement
- Fuel Type
- Diesel
- Connection
- Hose
- Housing Material
- Bronze (JMP aftermarket)
- Dimensions
- 34.0 cm L x 22.0 cm W x 22.0 cm H
- Weight
- 6.0 kg (13.25 lbs)
- Warranty
- 1 Year Limited (JMP aftermarket)
What’s in the Box
- 1 x Pump Assembly, Water (119578-42501)
Installation Notes
- Shut off the engine and allow it to cool completely. Close the seacock to prevent water ingress.
- Disconnect the negative battery terminal for safety.
- Loosen the hose clamps and carefully remove the inlet and outlet hoses from the pump. Note their orientation.
- Remove the mounting bolts that secure the old pump to the engine.
- Carefully detach the old pump assembly. Clean the mounting surface of any old gasket material or debris.
- Compare the new pump to the old one to confirm an identical fit.
- Install the new pump, tightening the mounting bolts to the manufacturer's specified torque.
- Reconnect the water hoses to the correct ports and tighten the clamps securely.
- Reconnect the battery terminal.
- Open the seacock fully.
- Start the engine and immediately check for any leaks at the pump body, gasket, and hose connections.
Troubleshooting & FAQ
How do I know if this pump fits my specific engine?
This pump is designed for the Yanmar 6LY3 series. The best way to confirm fitment is to match your existing part number to the ones listed in our Part Number Matrix (Yanmar 119578-42501, Johnson 10-13286-01, JMP JPR-YM06LY3). Also, check your engine model against the compatibility table provided on this page.
What are the signs of a failing water pump?
Common signs include engine overheating, visible water leaks from the pump housing or weep hole, a wobbly serpentine belt pulley, or unusual grinding/squealing noises from the pump area. Reduced water flow from the exhaust outlet is another key indicator.
How often should the impeller and service kits be used?
Impeller life varies based on usage, water conditions, and winterization. It is best practice to inspect the impeller annually and replace it every 1-2 years or every 200-300 hours of operation as preventative maintenance. The compatible JMP impeller is 7376-01. Major service kits (like JSK0127) should be used if you notice leaks or reduced performance.
Can I use OEM Yanmar service parts on this aftermarket pump?
Yes, this pump is designed to be compatible with both OEM and aftermarket service components. The JMP service kits (JSK0127, JSM0127) and impeller (7376-01 or OEM 119578-42550) are direct fits for both this pump and the original Yanmar pump.
Is this a self-priming pump?
Yes, marine raw water pumps of this design are typically flexible impeller pumps, which are self-priming. However, it's always good practice to ensure the system is properly primed after installation to prevent dry running, which can damage the impeller quickly.
What is the difference between this pump and the OEM version?
This is a high-quality aftermarket pump built to meet or exceed OEM specifications. The primary difference is the manufacturer; it is not made by Yanmar. It offers a cost-effective solution without compromising on materials (like the bronze housing) or performance.
OEM vs. Aftermarket?
This listing is an aftermarket replacement (not OEM). Built to OEM-level specifications with comparable materials. Manufactured in an ISO 9002 facility, batch-inspected for consistency.
Shipping speed & cost?
We ship worldwide quickly—typical transit 5–15 days. Standard shipping is free; expedited options appear at checkout where available.
Warranty & returns?
Covered by a 1-year warranty against manufacturing defects under normal use. If issues arise, contact support with your order details. Returns are accepted within our standard window (unused & in original condition). See our policy page or reach out for instructions.
Safety & Important Info
- Verify images/specifications vs your original part. If anything differs—even if your model appears compatible—do not purchase.
- This is an aftermarket replacement, not an OEM component.
- Professional installation is recommended for safety and performance.
About Sea Sierra
- Pro-Grade Standards — We supply marine parts engineered to OEM-level tolerances and tested for real-world conditions.
- Fast Global Fulfillment — Free standard delivery to most regions in 5–15 days.
- Manufacturer-Direct Value — Fair pricing without compromising on materials or QC.
Payment & Security
Payment methods
Your payment information is processed securely. We do not store credit card details nor have access to your credit card information.
