Mercury MerCruiser Quicksilver Gimbal Housing O-Ring 20863
Free returns on all eligible orders
You have 30 days to request a return. All sale items are final sale.
Part Details
- Part Number: 20863 / 25-20863
- Brand: Mercury Marine / Quicksilver
- GTIN / UPC: 745061130234
- Dimensions (cross-reference): 2-5/8 in. I.D. × 2-7/8 in. O.D. × 1/8 in. width
- System: Sealing — gimbal housing, bearing carrier, upper bearing housing
- Diagram Position: Gimbal housing assembly (MerCruiser transom); bearing carrier (select Mercury gear housings)
- Qty Per Assembly: 1
About This Part
Genuine Mercury Marine / Quicksilver 25-20863 is an OEM O-ring seal used in selected older MerCruiser and Mercury assemblies. In MerCruiser applications, Mercury parts diagrams place this O-ring directly in the gimbal housing assembly, where it seals the transom / sterndrive mounting interface. The same part number also appears in some older Mercury gear-housing diagrams as a bearing-carrier O-ring. Because Mercury reused this number across assemblies, the exact diagram position must be confirmed before ordering — appearance alone is not a reliable guide.
Compatible Applications
- Select MerCruiser sterndrive transom assemblies — gimbal housing O-ring position
- Older Mercury gear housings — bearing carrier sealing application
- Select small Mercury outboards — upper bearing housing sealing application
- Select Mercury / Mariner outboards: 4.5 HP, 7.5 HP, 45, 50, 55, 60, 75 HP (3-cylinder), 450, 500 series — confirm by serial number range
Always verify fitment using your engine or drive serial number and the exact Mercury / MerCruiser parts diagram before ordering.
Serial Number & Fitment Notice
For MerCruiser applications, confirm that the transom or gimbal-housing diagram specifically calls for 20863 / 25-20863. Mercury uses other O-rings in the same assemblies — including O-Ring 23145 in certain configurations — so using the exact diagram is the safest approach.
When to Replace
Replace this O-ring whenever the gimbal housing or mating housing is disassembled for service, or if the existing seal appears flattened, hardened, cracked, cut, swollen, or is actively leaking. Reusing a compressed or aged O-ring after reassembly risks repeat leaks.
Installation Notes
Clean the O-ring groove and all mating surfaces before installation. Inspect the surrounding gimbal housing for corrosion, burrs, or scoring. Install the new O-ring without twisting, stretching, or pinching it into the groove. Confirm the exact diagram position — this O-ring appears in multiple Mercury and MerCruiser assemblies.
Alternate & Cross-Reference Part Numbers
- OEM: 20863 / 25-20863
- Aftermarket (Sierra): 18-7152
- Aftermarket (GLM): 82310
- Related gimbal-housing O-ring (select assemblies): 23145
Parts Desk Insight
This O-ring is best treated as a diagram-specific seal rather than a generic replacement. In MerCruiser sterndrive applications it seats in the gimbal housing; in older Mercury outboard gear cases it appears as a bearing-carrier seal. A generic O-ring may look similar in diameter but can have the wrong cross-section or rubber compound, changing how it compresses and holds under load. Match by part number and diagram position — not by size or appearance alone.
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
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.