Upper Main Bearing – Fits Yamaha 20-30HP (Replaces 93311-632U7-00)
Upper Main Bearing – Fits Yamaha 20-30HP (Replaces 93311-632U7-00) 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
Upper Main Bearing – Fits Yamaha 20-30HP (Replaces 93311-632U7-00)
Product Details
This is a high-quality aftermarket Upper Main Bearing – Fits Yamaha 20-30HP (Replaces 93311-632U7-00), designed for Yamaha 20-30HP, 3-cylinder, 2-stroke outboard engines manufactured between 1993 and 2009. It serves as a crucial component within the crankshaft assembly, ensuring smooth engine operation.
It directly replaces OEM part 93311-632U7-00 and is interchangeable with WSM 93311-632U7 and Sierra 18-1377.
- Installation involves internal engine work.
- Designed for 2-stroke gasoline fuel systems.
- Critical for crankshaft support in 3-cylinder models.
Part Number Matrix
Use this matrix to confirm equivalent references across OEM and aftermarket.
| Brand | Part Number |
|---|---|
| Yamaha (OEM) | 93311-632U7-00 |
| WSM | 93311-632U7 |
| Sierra | 18-1377 |
| Aftermarket | 93311-632U7-00 |
Engine & Model Compatibility
Confirm your engine model/year in the table below.
This bearing fits a wide range of Yamaha 20HP, 25HP, and 30HP 2-stroke models. Please check your specific model and year for an exact match.
| Brand | Model | Rated HP | Stroke | Years | OEM Part No. | Notes |
|---|---|---|---|---|---|---|
| Yamaha | 20MLHU | 20 | 2-Stroke | 1996–1997 | 93311-632U7-00 | |
| Yamaha | 20MLHV | 20 | 2-Stroke | 1996–1997 | 93311-632U7-00 | |
| Yamaha | 20MSHU | 20 | 2-Stroke | 1996–1997 | 93311-632U7-00 | |
| Yamaha | 20MSHV | 20 | 2-Stroke | 1996–1997 | 93311-632U7-00 | |
| Yamaha | 25ELH, 25ESH, 25MLH, 25MSH | 25 | 2-Stroke | 1994–2009 | 93311-632U7-00 | Various models with different shaft length/steering options |
| Yamaha | 25ELHT, 25ELHW, 25ELHX | 25 | 2-Stroke | 1994–2009 | 93311-632U7-00 | Tiller models with different year suffixes |
| Yamaha | 25ELHU, 25ELHV | 25 | 2-Stroke | 1994–2009 | 93311-632U7-00 | |
| Yamaha | 25ELR, 25ESR | 25 | 2-Stroke | 1994–2009 | 93311-632U7-00 | Remote control models |
| Yamaha | 25ELRT, 25ELRU, 25ELRV | 25 | 2-Stroke | 1994–2009 | 93311-632U7-00 | |
| Yamaha | 25ELRW, 25ELRX | 25 | 2-Stroke | 1994–2009 | 93311-632U7-00 | |
| Yamaha | 25ESHT, 25ESHU, 25ESHV | 25 | 2-Stroke | 1994–2009 | 93311-632U7-00 | |
| Yamaha | 25ESHW, 25ESHX | 25 | 2-Stroke | 1994–2009 | 93311-632U7-00 | |
| Yamaha | 25MLHT, 25MLHU, 25MLHV | 25 | 2-Stroke | 1994–2009 | 93311-632U7-00 | |
| Yamaha | 25MLHW, 25MLHX, 25MLHZ | 25 | 2-Stroke | 1994–2009 | 93311-632U7-00 | |
| Yamaha | 25MSHT, 25MSHU, 25MSHV | 25 | 2-Stroke | 1994–2009 | 93311-632U7-00 | |
| Yamaha | 25MSHW, 25MSHX, 25MSHZ | 25 | 2-Stroke | 1994–2009 | 93311-632U7-00 | |
| Yamaha | 25MSHB, 25MSHC, 25MSHD | 25 | 2-Stroke | 2003–2009 | 93311-632U7-00 | Later model variants |
| Yamaha | 30ELHS, 30ELHT, 30ELHU | 30 | 2-Stroke | 1993–2002 | 93311-632U7-00 | |
| Yamaha | 30ELHV, 30ELHW, 30ELHX | 30 | 2-Stroke | 1993–2002 | 93311-632U7-00 | |
| Yamaha | 30ELHY, 30ELHZ | 30 | 2-Stroke | 1993–2002 | 93311-632U7-00 | |
| Yamaha | 30ELRR, 30ELRS, 30ELRT | 30 | 2-Stroke | 1993–2002 | 93311-632U7-00 | |
| Yamaha | 30ELRU, 30ELRV, 30ELRW | 30 | 2-Stroke | 1993–2002 | 93311-632U7-00 | |
| Yamaha | 30ELRX, 30ELRY, 30ELRZ | 30 | 2-Stroke | 1993–2002 | 93311-632U7-00 | |
| Yamaha | 30ESRR, 30ESRS, 30ESRT | 30 | 2-Stroke | 1993–2002 | 93311-632U7-00 | |
| Yamaha | 30ESRU, 30ESRV, 30ESRW | 30 | 2-Stroke | 1993–2002 | 93311-632U7-00 | |
| Yamaha | 30MLHR, 30MLHS, 30MLHT | 30 | 2-Stroke | 1993–2002 | 93311-632U7-00 | |
| Yamaha | 30MLHU, 30MLHV, 30MLHW | 30 | 2-Stroke | 1993–2002 | 93311-632U7-00 | |
| Yamaha | 30MLHX, 30MLHY, 30MLHZ | 30 | 2-Stroke | 1993–2002 | 93311-632U7-00 | |
| Yamaha | 30MSHR, 30MSHS, 30MSHT | 30 | 2-Stroke | 1993–2002 | 93311-632U7-00 | |
| Yamaha | 30MSHU, 30MSHV, 30MSHW | 30 | 2-Stroke | 1993–2002 | 93311-632U7-00 | |
| Yamaha | 30MSHX, 30MSHY, 30MSHZ | 30 | 2-Stroke | 1993–2002 | 93311-632U7-00 | |
| Yamaha | 30MSHA | 30 | 2-Stroke | 2002 | 93311-632U7-00 | |
| Yamaha | C30ELRR, C30ELRS | 30 | 2-Stroke | 1993–1994 | 93311-632U7-00 | Commercial models |
| Yamaha | C30ELRT, C30ELRU | 30 | 2-Stroke | 1995–1996 | 93311-632U7-00 | Commercial models |
| Yamaha | C30ELHT | 30 | 2-Stroke | 1995 | 93311-632U7-00 | Commercial model |
| Yamaha | C30MLHS, C30MLHT | 30 | 2-Stroke | 1994–1995 | 93311-632U7-00 | Commercial models |
Technical Specs
- Product Type
- Crankshaft Upper Main Bearing
- Installation
- Internal Engine Component
- Fuel Type
- 2-Stroke Gasoline
- Dimensions
- 6.0 x 6.0 x 5.0
- Weight
- 208 g (0.46 lb)
- Other Attributes
- For use in 3-cylinder outboard crankshaft assembly
What’s in the Box
- 1 x Upper Main Bearing (93311-632U7-00)
Installation Notes
- Disconnect the battery and ensure the engine is off and cool.
- Carefully disassemble the engine powerhead to access the crankshaft. Follow your service manual’s specific procedure.
- Remove the old upper main bearing from the crankshaft assembly, noting its orientation.
- Clean the bearing seat and surrounding area of any debris or old oil.
- Lubricate the new bearing with clean 2-stroke engine oil.
- Press the new bearing into place, ensuring it is properly seated. A bearing press is recommended.
- Reassemble the engine components in reverse order of disassembly, torquing all bolts to manufacturer specifications.
- Once fully assembled, reconnect the battery and test the engine at low RPM, listening for any unusual noises.
Troubleshooting & FAQ
How do I know if this is the correct bearing for my engine?
This bearing fits specific Yamaha 20-30HP 3-cylinder, 2-stroke models from 1993–2009. The most reliable way to confirm fitment is to match your engine's model and year to our compatibility table and verify the OEM part number 93311-632U7-00 against your service manual.
What are the signs of a failing upper main bearing?
Common symptoms include a knocking or rumbling sound from the upper part of the engine, increased vibration, or noticeable vertical play in the crankshaft. Failure can lead to catastrophic engine damage, so it is critical to address these signs immediately.
Can I replace just the upper bearing?
While you can replace a single failed bearing, it is often recommended to replace all main and connecting rod bearings during an engine rebuild. This ensures consistent wear and performance, preventing premature failure of other older components.
Is a special tool required for installation?
Yes, installation of an internal engine bearing typically requires a bearing press or a suitable driver to ensure it is seated correctly without being damaged. A torque wrench is also essential for reassembly. Professional installation is highly recommended.
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.
