Front Seal Cover Gasket – Fits Yanmar 3JH25A Marine Diesel Engines (Replaces 129150-01531)
Front Seal Cover Gasket – Fits Yanmar 3JH25A Marine Diesel Engines (Replaces 129150-01531) is backordered and will ship as soon as it is back in stock.
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Worry-free returns
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Delivery and Shipping
Delivery and Shipping
Free standard shipping on all orders under 1 KG
Front Seal Cover Gasket – Fits Yanmar 3JH25A Marine Diesel Engines ...
Product Details
This is a direct replacement Front Seal Cover Gasket designed to fit Yanmar 3JH25A 25 HP, 3-cylinder marine diesel engines manufactured between 1986–2012. It ensures a reliable seal for the front seal cover on the engine's gear housing.
This part serves as an aftermarket equivalent for Yanmar OEM part number 129150-01531.
- Installs as a direct replacement for the original part.
- Specifically designed for the front seal cover on the engine gear housing.
- Made from durable gasket material to prevent leaks and ensure longevity.
Part Number Matrix
Use this matrix to confirm equivalent references across OEM and aftermarket.
| Brand | Part Number |
|---|---|
| Yanmar | 129150-01531 |
Engine & Model Compatibility
Confirm your engine model/year in the table below.
This part is compatible with select Yanmar marine diesel engines.
| Brand | Model | Rated HP | Stroke | Years | OEM Part No. | Notes |
|---|---|---|---|---|---|---|
| Yanmar | 3JH25A | 25 | 4-Stroke | 1986–2012 | 129150-01531 |
Technical Specs
- Product Type
- Front Seal Cover Gasket
- Application
- Used for the front seal cover on engine gear housing
- Installation
- Direct replacement
- Fuel Type
- Diesel
- Material
- Gasket material (composition not specified)
- Dimensions
- 24.0 cm x 21.0 cm x 0.1 cm
What’s in the Box
- 1 x Front Seal Cover Gasket (Replaces 129150-01531)
Installation Notes
- Ensure the engine is turned off, cool to the touch, and the battery is disconnected for safety.
- Locate and access the engine's front seal cover. This may require removing other components.
- Carefully remove the bolts securing the cover and detach it from the gear housing.
- Remove the old gasket completely. Use a plastic scraper to avoid gouging the metal surfaces.
- Thoroughly clean both the housing and cover mating surfaces of any old gasket material, sealant, or oil.
- Ensure both surfaces are clean, dry, and free from any scoring or damage before proceeding.
- Position the new gasket correctly onto the gear housing, ensuring all bolt holes are aligned.
- Re-install the front seal cover and tighten the bolts in a crisscross pattern to the manufacturer's recommended torque specifications.
- Reconnect the battery, start the engine, and carefully inspect the cover area for any signs of oil leakage.
Troubleshooting & FAQ
How do I know if this gasket fits my engine?
This gasket is specifically for the Yanmar 3JH25A model (25 HP, 1986–2012). Always verify your engine model and confirm it cross-references with the OEM part number 129150-01531 before ordering.
What are the signs of a failing front seal cover gasket?
Common symptoms include oil leaks from the front of the engine, typically around the gear housing or crankshaft pulley area. A visibly degraded, brittle, or cracked gasket is also a clear sign it needs replacement.
Do I need to use sealant with this gasket?
Typically, this type of gasket is designed to be installed dry. However, always consult your engine's specific service manual, as some applications may recommend a thin, even layer of an appropriate sealant.
How often should this gasket be replaced?
There is no fixed replacement interval for this gasket. It should be replaced whenever the front seal cover is removed for service, or immediately if an oil leak is detected in that area.
OEM vs. Aftermarket?
This listing is an aftermarket replacement (not OEM). It is 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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