Mercury MerCruiser Quicksilver Gimbal Housing Washer 21900
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Mercury MerCruiser Quicksilver 12-21900 is a genuine Mercury Marine flat washer used in select MerCruiser sterndrive, transom, and gimbal housing assemblies. Mercury parts references commonly show this washer used at the gimbal housing bolt location, where it works with the related bolt and nut hardware to support proper clamping and load distribution.
Key Features
- Genuine Mercury Marine / Quicksilver washer reference
- Commonly used as a gimbal housing bolt washer in supported MerCruiser assemblies
- OEM part number: 12-21900
- Base part reference: 21900
- GTIN / UPC reference: 745061130609
- Catalog package reference: approximately 1.00 in. x 1.00 in. x 0.10 in.
- Catalog weight reference: approximately 0.02 lb
Engine Compatibility
This washer is shown across a broad range of MerCruiser applications, including select older 120/140, 160, 165, 225-S, 228, 233, 250, 260, 470, 485, 888, 898, early MerCruiser sterndrive assemblies, R/MR/Alpha One, Alpha One Gen II, and related transom assembly applications depending on serial number range. It is also commonly described as a genuine MerCruiser sterndrive flat washer found on Alpha 1, Alpha 1 Gen 2, Bravo 1, Bravo 2, and Bravo 3 sterndrives.
Serial Number Fitment Notice
Washer fitment depends on the exact drive, transom assembly, gimbal housing, hardware stack, and serial number range. Always confirm compatibility using the MerCruiser serial number and the exact parts diagram before ordering, especially when replacing gimbal housing or transom hardware.
When This Part Needs Replacement
Replace this washer if it is missing, corroded, bent, distorted, worn, crushed, or damaged during removal. A washer in poor condition may not distribute clamping load correctly and should not be reused in a critical sterndrive or transom hardware location.
Installation Notes
Confirm the washer’s exact location in the MerCruiser parts diagram before installation. Mercury diagrams commonly show 21900 used with related gimbal housing bolt hardware, including nut reference 34087 in supported assemblies. Inspect the bolt, nut, mating surfaces, and surrounding transom or gimbal hardware while the area is apart.
Alternate/Superseded Part Numbers
- 12-21900
- 21900
- Mercury Marine 21900
- Quicksilver 12-21900
- Related hardware reference: 11-34087 nut, used with the gimbal housing bolt hardware stack in supported diagrams
Parts Desk Insight
This washer is a small part, but the location matters. If it is being used in a gimbal housing or transom assembly, match it by the exact MerCruiser diagram callout rather than substituting a generic washer by size or appearance.
Shipping: Ships same or next day for fast Canada wide shipping. ⚓
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.