Water Pump Gasket – Fits Yanmar 3JH & 4JH Marine Diesel Engines (Replaces 129486-42050)
Water Pump Gasket – Fits Yanmar 3JH & 4JH Marine Diesel Engines (Replaces 129486-42050) is backordered and will ship as soon as it is back in stock.
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Delivery and Shipping
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Water Pump Gasket – Fits Yanmar 3JH & 4JH Marine Diesel Engines...
Product Details
This high-quality Water Pump Gasket is engineered to create a reliable seal between the freshwater pump and the engine block on various Yanmar marine and industrial diesel engines. It is designed for a precise fit on popular 3JH and 4JH marine series engines, as well as 3TNE, 3TNV, and 4TNV industrial models.
It serves as a direct replacement for Yanmar part numbers 129486-42050 and 129150-42020.
- Installs between the water pump and engine block.
- Designed for diesel fuel engine applications.
- Constructed from durable gasket paper for a lasting seal.
Part Number Matrix
Use this matrix to confirm equivalent references across OEM and aftermarket.
| Brand | Part Number |
|---|---|
| Yanmar | 129486-42050 |
| Yanmar | 129150-42020 |
Engine & Model Compatibility
Confirm your engine model/year in the table below.
For Yanmar marine and industrial engines, verify your model against the lists to ensure correct fitment.
| Brand | Model | Stroke | OEM Part No. | Notes |
|---|---|---|---|---|
| Yanmar | 3JH2, 3JH2Z | 4-Stroke | 129486-42050 | |
| Yanmar | 3JH3, 3JH3E, 3JH3CE | 4-Stroke | 129486-42050 | |
| Yanmar | 3JH3Z, 3JH3Z1, 3JH3Z2 | 4-Stroke | 129486-42050 | |
| Yanmar | 3JH4E | 4-Stroke | 129486-42050 | |
| Yanmar | 3JH5E | 4-Stroke | 129486-42050 | |
| Yanmar | 4JH, 4JH-HT, 4JH-HTE, 4JH-T, 4JH-TE, 4JHE | 4-Stroke | 129486-42050 | |
| Yanmar | 4JH2E, 4JH2-DTE, 4JH2-HTE, 4JH2-TE | 4-Stroke | 129486-42050 | |
| Yanmar | 4JH2-UTB, 4JH2-UTE | 4-Stroke | 129486-42050 | |
| Yanmar | 4JH3, 4JH3E, 4JH3CE, 4JH3CE1, 4JH3-DTE | 4-Stroke | 129486-42050 | |
| Yanmar | 4JH3-HTE, 4JH3-TE, 4JH3-TCE, 4JH3ZA | 4-Stroke | 129486-42050 | |
| Yanmar | 4JH4-HTE, 4JH4-TE, 4JH4AE, 4JH4E | 4-Stroke | 129486-42050 |
| Brand | Model | Stroke | OEM Part No. | Notes |
|---|---|---|---|---|
| Yanmar | 3TNE78E | 4-Stroke | 129486-42050 | |
| Yanmar | 3TNE82A, 3TNE82A-EYB | 4-Stroke | 129486-42050 | |
| Yanmar | 3TNE84, 3TNE84T | 4-Stroke | 129486-42050 | |
| Yanmar | 3TNC78E | 4-Stroke | 129486-42050 | |
| Yanmar | 3TNV88, 3TNV88-GKM | 4-Stroke | 129486-42050 | |
| Yanmar | 3TNV84T-GYM | 4-Stroke | 129486-42050 | |
| Yanmar | 4TNV88-MJTLB | 4-Stroke | 129486-42050 | |
| Yanmar | 4TNV88-BDHQ, 4TNV88-BDHQ(T), 4TNV88-BDSA | 4-Stroke | 129486-42050 |
For John Deere equipment, this part is compatible with models that utilize specific Yanmar engines. Cross-reference your equipment's part number to confirm.
| Brand | Model | Stroke | OEM Part No. | Notes |
|---|---|---|---|---|
| John Deere | 655, 755, 855 Tractors | 4-Stroke | 129150-42020/129486-42050 | Uses Yanmar engines |
| John Deere | 4300, 4310, 4400, 4600, 4700 Tractors | 4-Stroke | 129150-42020/129486-42050 | Uses Yanmar engines |
| John Deere | 990, 2520, 3120 Tractors | 4-Stroke | 129150-42020/129486-42050 | Uses Yanmar engines |
Technical Specs
- Product Type
- Water Pump Gasket
- Installation
- Between water pump and engine block
- Fuel Type
- Diesel
- Material
- Gasket Paper
- Dimensions
- Approximately 13.0" × 6.5" × 0.1"
- Warranty
- 6 months (Genuine Yanmar)
- OEM Status
- Available as Genuine Yanmar or Aftermarket
What’s in the Box
- 1 x Water Pump Gasket (129486-42050)
Installation Notes
- Ensure the engine is cool and disconnect the battery. Drain the cooling system as per the manufacturer's guidelines.
- Remove any components obstructing access to the water pump assembly.
- Carefully unbolt and remove the existing water pump from the engine block.
- Thoroughly clean both the engine block and water pump mating surfaces. Ensure all old gasket material, sealant, and residue are completely removed for a clean surface.
- Position the new gasket onto the engine block, ensuring it aligns perfectly with the bolt holes.
- Reinstall the water pump over the new gasket. Hand-tighten bolts initially, then torque them to the manufacturer's specified value in a crossing or star pattern to ensure even pressure.
- Reconnect all previously removed components, refill the cooling system with the appropriate coolant, and inspect for immediate leaks.
Troubleshooting & FAQ
How do I know if my water pump gasket is failing?
Common signs of a failed water pump gasket include visible coolant leaks from the area where the water pump meets the engine block, unexplained coolant loss, engine overheating alarms, or a sweet smell of antifreeze around the engine bay. Check for stains or drips directly below the pump.
Will this fit my raw water (seawater) pump?
No, this gasket is specifically designed for the freshwater circulation pump that mounts directly to the engine block. It is not intended for use on the raw water (seawater) pump, which uses different gaskets and seals.
Is any sealant required during installation?
This gasket is designed to be installed dry on clean, flat surfaces. Most service manuals do not recommend sealant. However, if the mating surfaces have minor imperfections, a very thin, even coat of a high-quality gasket sealant rated for coolant systems may be applied, but always consult your engine's service manual first.
What is the difference between part 129486-42050 and 129150-42020?
Part number 129486-42050 is a direct replacement that supersedes 129150-42020. They are functionally identical, have the same form and fit, and are interchangeable for all listed engine applications.
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.
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