Pinion Lower Bearing – Fits OMC Sterndrive (Replaces OMC 983892, 0983892; Mercury 31-812767A1, 8M0103476)
Pinion Lower Bearing – Fits OMC Sterndrive (Replaces OMC 983892, 0983892; Mercury 31-812767A1, 8M0103476) is backordered and will ship as soon as it is back in stock.
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Delivery and Shipping
Delivery and Shipping
Free standard shipping on all orders under 1 KG
Pinion Lower Bearing – Fits OMC Sterndrive (Replaces OMC 983892, 09...
Product Details
This Pinion Lower Bearing is a crucial replacement component for the gearcase assembly in specific marine engines. It is engineered to fit OMC Cobra Sterndrive models from 1986–1993 and a range of Mercury/Mariner 40-60 HP 2-Stroke and 4-Stroke outboards, ensuring smooth gear operation.
This part serves as a direct replacement for OEM part numbers including OMC 983892 and 0983892, as well as Mercury 31-812767A1 and 8M0103476. It also interchanges with aftermarket parts from Red Rhino, Green Bay Prop, and Sierra.
- Installation Location: Installs within the gearcase assembly.
- OMC Application: Specifically used in the upper gear case of OMC Cobra (1986–1993) sterndrives.
- Mercury/Mariner Application: Used in the gearcase assembly for various 40-60 HP models.
Part Number Matrix
Use this matrix to confirm equivalent references across OEM and aftermarket.
| Brand | Part Number |
|---|---|
| OMC | 983892 |
| OMC | 0983892 |
| Mercury | 31-812767A1 |
| Mercury | 8M0103476 |
| Red Rhino | 983892 |
| Green Bay Prop | 983892 |
| Sierra | 18-2165 |
| Sierra | 1170 |
Engine & Model Compatibility
Confirm your engine model/year in the table below.
OMC: Designed for Cobra Sterndrive models manufactured between 1986 and 1993.
Mercury/Mariner: Fits various 40–60 HP 2-Stroke & 4-Stroke models as detailed below.
| Brand | Model | Rated HP | Stroke | Years | OEM Part No. | Notes |
|---|---|---|---|---|---|---|
| OMC Power Products | Cobra Sterndrive | 1986–1993 | 983892/0983892 | Used in upper gear case | ||
| Mercury/Mariner | 50 (3-Cyl.) | 50 | 2-Stroke | 31-812767A1/812767A1 | Gearcase Assy | |
| Mercury/Mariner | 55 (3-Cyl.) | 55 | 2-Stroke | 31-812767A1/812767A1 | Gearcase Assy | |
| Mercury/Mariner | 60 (3-Cyl.) | 60 | 2-Stroke | 31-812767A1/812767A1 | Gearcase Assy | |
| Mercury/Mariner | 40 EFI | 40 | 4-Stroke | 31-812767A1/812767A1 | Gearcase Assy | |
| Mercury/Mariner | 50 EFI | 50 | 4-Stroke | 31-812767A1/812767A1 | Gearcase Assy | |
| Mercury/Mariner | 60 EFI | 60 | 4-Stroke | 31-812767A1/812767A1 | Gearcase Assy |
Technical Specs
- Product Type
- Lower Pinion Bearing
- Installation Area
- Gearcase Assembly
- Product Dimensions
- 3.5" x 3.44" x 1.31" (H x W x L)
What’s in the Box
- 1x Pinion Lower Bearing
Installation Notes
- Disconnect the battery cables and ensure the engine is off and cool before beginning work.
- Completely drain the gearcase lubricant into a suitable container.
- Following your official service manual, disassemble the lower unit to access the pinion gear and bearing assembly.
- Carefully remove the worn pinion bearing, noting the orientation and any adjacent shims or washers.
- Clean all mating surfaces thoroughly and inspect the pinion gear for any signs of wear or damage.
- Using a bearing press and the correct drivers, install the new bearing squarely into its housing. Do not use a hammer.
- Reassemble the gearcase components in the reverse order of disassembly.
- Ensure all bolts and fasteners are torqued to the manufacturer's specified values.
- Refill the gearcase with the recommended type and volume of fresh marine gear lubricant.
- After reassembly, rotate the propeller shaft by hand to check for smooth operation before starting the engine.
Troubleshooting & FAQ
How do I know if this pinion bearing fits my specific engine?
This bearing is designed for OMC Cobra Sterndrives (1986–1993) and a range of Mercury/Mariner 40-60 HP models. To guarantee fitment, please check your OEM part number against our Part Number Matrix and review the compatibility table. "Cobra" or your engine's horsepower alone is not enough to confirm.
What are the signs of a failing pinion bearing?
Common symptoms include a distinct grinding, whining, or rumbling noise from the lower unit that changes with engine RPM. You may also notice excessive vibration during operation or discover metal shavings (glitter) in the gear lube during a fluid change.
Is this bearing used in the upper or lower gearcase?
This is a lower pinion bearing. It is installed within the main gearcase assembly. For the OMC Cobra models listed, it is specifically located in the upper gear case section of the sterndrive.
Can I replace this bearing myself?
This repair is considered advanced. It requires specialized tools like a bearing puller, a press, and dial indicators for checking gear backlash. We strongly recommend professional installation by a qualified marine mechanic to ensure proper alignment, shimming, and longevity.
Why are so many different part numbers listed?
We list all known equivalent part numbers from different brands (OEMs like OMC and Mercury) and aftermarket manufacturers (e.g., Sierra, Red Rhino) to simplify your search. All part numbers in the matrix are interchangeable with this product.
When should a pinion bearing be replaced?
Pinion bearings do not have a set replacement interval. They should only be replaced if they show signs of failure, such as noise, vibration, or damage discovered during a gearcase service. They are not typically replaced as part of routine preventative maintenance.
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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