Quicksilver O-Ring 29976 – Mercury MerCruiser OEM
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Quicksilver O-Ring 29976
This genuine OEM O-ring is used throughout Mercury and MerCruiser engine and drive assemblies to seal fluid passages, housings, and fittings against oil, water, and fuel intrusion. O-rings are a one-time-use seal — every time a joint is disassembled, a fresh O-ring should go back in. Using the correct OEM part ensures the right compound, durometer, and dimensional fit, all of which directly affect how long the seal holds up under heat, pressure, and marine exposure.
Key Specifications
- Part Number: 29976 (OEM ref: 25-29976)
- Type: O-Ring
- Genuine OEM — not aftermarket
Common Applications
Use this O-ring wherever the Mercury or MerCruiser parts diagram specifies part number 29976. It appears across multiple engine families and drive configurations — always verify against your model’s current parts diagram, serial number, and assembly location before ordering.
When to Replace
Replace any time you disassemble a sealed joint and the existing O-ring shows signs of flattening, cracking, hardening, swelling, or surface contamination. Always install a fresh O-ring on reassembly — never reuse the old part.
Installation Notes
Clean mating surfaces thoroughly before installation. Lightly lubricate the O-ring with the appropriate fluid (fuel-safe grease or the system fluid) to ease installation and prevent tearing. Follow the Mercury service manual for orientation and torque specifications on the surrounding hardware.
Related Products
Parts Desk Insights
Best used as a direct OEM replacement during fuel system, cooling system, or drive service where the parts diagram calls for 29976. This O-ring is a common inclusion in rebuild and reseal jobs on MerCruiser sterndrive and Mercury outboard assemblies — it’s worth ordering a spare to have on hand if you’re doing a full service. Always match by part number: O-rings that look identical can differ in compound and will fail prematurely in the wrong application. If your assembly has been repowered or updated, cross-reference the current diagram to confirm this number hasn’t been superseded.
Shipping information
In-stock and OEM parts: ship same or next business day.
Locally warehoused items: ship within 3–4 business days.
Special-order items: timeline confirmed after order.
Returns & warranty
Returns & Satisfaction Guarantee
We stand firmly behind the quality of every product we sell. Your confidence matters to us — and we back it with a straightforward 30-Day Satisfaction Guarantee.
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.
To qualify for a return:
Item must be in new, unused condition
Product must be in its original packaging
All parts, components, hardware, manuals, and accessories must be included
Packaging must be undamaged and suitable for resale
Important:
Electronics are strictly inspected. No returns on open-box electronics. Exceptions may apply only with prior written approval. Any electronic unit that has been installed, powered, activated, or altered may not be eligible for return.
We are serious about product integrity — and equally serious about taking care of our customers. If there is ever a product issue, contact us immediately so we can make it right.
For return authorization, please contact our support team before shipping anything back.