Mercury MerCruiser Quicksilver Bearing Carrier O-Ring 29976
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Mercury MerCruiser Quicksilver Bearing Carrier O-Ring – Part Number 29976
- Part Number: 29976 | OEM Service Number: 25-29976
- Brand: Mercury Marine / Quicksilver
- Type: Bearing Carrier O-Ring — OEM Replacement Seal
- GTIN: 745061133778
- Superseded By: No current superseding Mercury number identified. 29976 / 25-29976 remains active in Mercury parts references.
- System: Lower Unit / Gearcase — Propeller Shaft Section
- Diagram Position: Seated directly ahead of the bearing carrier in the propeller-shaft section of the gear housing; typically 1 required per gearcase assembly.
What This Part Does
The bearing carrier O-ring seals the bearing carrier against the gear housing bore, retaining gear lubricant inside the lower unit and blocking water intrusion into the gearcase. It is a one-time-use seal — a fresh O-ring should be installed any time the bearing carrier is removed.
Compatible Applications
- Selected Mercury outboard gear housing assemblies (verify by serial number and current parts diagram)
- Older MerCruiser sterndrive gearcase assemblies (verify by serial number and current parts diagram)
Mercury has used several different bearing carrier O-rings across outboard and sterndrive gearcases. Seals that appear identical are not necessarily interchangeable. Confirm fit using your engine or drive serial number and the factory parts diagram before ordering.
When to Replace
- Any time the bearing carrier is removed
- Existing O-ring is flattened, cracked, hardened, or cut
- Gear lubricant leaking around the bearing carrier
- Water contamination found in gear oil
- Gearcase resealing or rebuild service
- Propeller-shaft or bearing-carrier service
Installation Notes
- Clean the O-ring groove and all mating surfaces before installation
- Inspect the bearing carrier and gear housing for corrosion, scoring, or debris
- Lightly lubricate the O-ring prior to installation per the applicable Mercury service procedure
- Do not twist, stretch, or pinch the O-ring during carrier installation
- After service, refill with specified gear lubricant and pressure-test the lower unit as required
Alternate Part Numbers
- Mercury 29976
- Mercury / Quicksilver 25-29976
- Sierra 18-7157 (aftermarket cross-reference)
Related Parts
- Quicksilver Bearing Carrier Key 30281 – Mercury MerCruiser OEM
- Mercury MerCruiser Alpha One Gen II Bearing Carrier Assembly 14587A7
- Mercury MerCruiser Bearing Carrier Seal – Inside, 26-14077
- Mercury MerCruiser Bearing Carrier Retaining Ring 35128
- Shop All Marine Gaskets, Seals & O-Rings
Parts Desk Insights
The bearing carrier O-ring is one of the most commonly mixed-up seals in Mercury lower unit service — several O-rings look nearly identical but differ in compound and dimensions. Matching by exact part number (29976 / 25-29976) and confirming against your gearcase parts diagram is essential. This part is a standard inclusion in any bearing carrier or propeller-shaft reseal job; ordering a spare is worthwhile if you are doing a full lower unit service.
Shipping information
In-stock and OEM parts: ship same or next business day.
Locally warehoused items: ship within 1-3 business days.
Special-order items: timeline confirmed after order.
Returns & warranty
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If you are not fully satisfied, you may request a return within 30 days of delivery. All returns must receive pre-approval prior to being sent back. Unauthorized returns will not be accepted.
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Important:
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