Crankshaft Upper Bearing – Fits Yamaha 40-50HP 2-Stroke Outboard (Replaces 93306-305U8-00)
Crankshaft Upper Bearing – Fits Yamaha 40-50HP 2-Stroke Outboard (Replaces 93306-305U8-00) is backordered and will ship as soon as it is back in stock.
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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.).
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Delivery and Shipping
Delivery and Shipping
Free standard shipping on all orders under 1 KG
Crankshaft Upper Bearing – Fits Yamaha 40-50HP 2-Stroke Outboard (R...
Product Details
This Crankshaft Upper Bearing is a high-quality replacement part designed for Yamaha 40-50HP 2-Stroke outboard engines manufactured from 1984 to 1998. As a critical internal component, it ensures smooth and reliable operation of your engine's crankshaft.
This part serves as a direct interchange for Yamaha OEM numbers 93306-305U8-00 and its successor 93306-305U2-00. It is made to the same specifications as the KOYO bearing, which was an original equipment supplier to Yamaha.
- Installation: Fits as an internal engine component, requiring engine disassembly.
- Bearing Type: Precision ball bearing construction.
- Guaranteed Quality: Backed by a 1-year warranty from SAIL MARINE.
Part Number Matrix
Use this matrix to confirm equivalent references across OEM and aftermarket.
| Brand | Part Number | Notes |
|---|---|---|
| Yamaha | 93306-305U8-00 | Superseded by 93306-305U2-00 |
| Yamaha | 93306-305U2-00 | Current replacement part number |
| KOYO Bearing | - | Original OEM supplier equivalent |
Engine & Model Compatibility
Confirm your engine model/year in the table below.
| Brand | Model | Rated HP | Stroke | Years | OEM Part No. |
|---|---|---|---|---|---|
| Yamaha | 40-50HP Models | 40-50 | 2-Stroke | 1984–1998 | 93306-305U8-00 |
Technical Specs
- Product Type
- Crankshaft Upper Bearing
- Installation
- Internal engine component
- Dimensions
- 9.0 x 9.0 x 3.5 inches
- Color
- Black
- Warranty
- 1 Year (SAIL MARINE)
- Bearing Type
- Ball bearing
What’s in the Box
- 1 x Crankshaft Upper Bearing (Replaces 93306-305U8-00)
Installation Notes
- Disconnect the battery and all ignition system connections for safety.
- Following the manufacturer's service manual, drain the engine oil completely.
- Carefully disassemble the powerhead to gain access to the crankshaft assembly.
- Remove the old upper bearing, paying close attention to its orientation and any associated seals or clips.
- Thoroughly clean the crankshaft journal and the bearing seat in the engine block.
- Liberally apply a quality engine assembly lubricant to the new bearing and the journal.
- Press the new bearing into place, ensuring it is properly seated and aligned.
- Reassemble the engine, making sure to torque all fasteners to the specified values.
- Refill with fresh engine oil to the correct level before attempting to start the engine.
Troubleshooting & FAQ
How do I know if my crankshaft bearing is failing?
Key symptoms of a bad crankshaft bearing include a persistent knocking or rumbling sound from the engine, a drop in oil pressure, or discovery of metallic shavings in the engine oil during an oil change. If you notice any of these signs, an immediate inspection is required.
Is this part compatible with a Yamaha 4-stroke engine?
No. This bearing is specifically designed for the Yamaha 40-50HP 2-Stroke outboard series from 1984–1998. Using it in a 4-stroke or other incompatible model will result in engine damage.
Do I need to lubricate this bearing before installation?
Yes. The bearing is shipped dry. It is essential to lubricate it with a high-quality engine assembly lube and apply a film of fresh engine oil to all contact surfaces before and during installation to prevent premature failure.
What is the difference between an upper and lower crankshaft bearing?
Upper and lower bearings are positioned at different ends of the crankshaft and are designed to handle different specific loads. They are not interchangeable. Always use the exact part number specified for each location.
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
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