Seachoice 50-21009 Full-Flow Oil Filter – Mercury & Honda 4-Stroke Outboard, 20 Micron
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Seachoice 50-21009 Full-Flow Marine Oil Filter
Part Number: 50-21009 | Brand: Seachoice | UPC: 719249210094
A 20-micron full-flow spin-on oil filter for Mercury FourStroke and Honda 4-stroke outboard engines. High-efficiency cellulose media captures contaminants before they circulate through the lubrication system, while the epoxy-coated canister stands up to salt air and spray. The anti-drain-back valve keeps oil pressure stable between starts for consistent protection at every startup.
Features
- 20-micron full-flow filtration — high-efficiency cellulose media
- Anti-drain-back valve maintains oil pressure between starts
- Epoxy-coated canister for corrosion resistance
- Reinforced body construction and heavy-duty end-cap seals
- Manufactured in an ISO/TS 16949 certified facility
Compatible Applications
- Mercury / Quicksilver FourStroke outboards — replaces 35-822626Q03 and 35-822626Q1
- Honda 4-stroke outboards — replaces 15400-PFB-014
Confirm your engine model, year, serial number, and existing filter part number before ordering. Mercury and Honda use several physically similar filters across different 4-stroke families. If your engine requires the later Mercury 35-822626Q15 or Q7 revision, see the Seachoice 50-21011.
Service Interval
Replace at the outboard manufacturer's recommended oil-change interval. Regular filter replacement prevents accumulated contaminants from circulating through bearings and lubricated engine components.
Installation Notes
Remove the old filter and verify its sealing gasket comes away with it. Clean the mounting surface, lightly coat the replacement gasket with fresh engine oil, install hand-tight plus per the engine manufacturer's specification, and inspect for leaks after first startup.
Cross-Reference Part Numbers
- Seachoice: 50-21009 / 21009
- Sierra: 18-7913
- Mercury / Quicksilver: 35-822626Q03 / 35-822626Q1
- Honda: 15400-PFB-014
- Mallory: 9-57800
Related Products
- Sierra 18-7913 4-Cycle Outboard Oil Filter – Mercury & Honda
- Seachoice 50-21011 Full-Flow Oil Filter – Mercury & Yamaha Outboard
- Seachoice 50-21004 Full-Flow Oil Filter – Mercury & Mariner Outboard
- Mercury 8M0162832 OEM Oil Filter – FourStroke 8–30 HP Outboard
- Mallory 9-57800 Marine Oil Filter – Mercury, Mariner & Honda Outboards
Parts Desk Insights
This filter is most commonly ordered for routine oil changes on smaller Mercury FourStroke and Honda BF-series outboards. The quickest fitment confirmation is the Sierra 18-7913 cross-reference — if that number matches your engine's service manual, you're in the right filter family. The most common customer error is confusing this with the later Mercury 35-822626Q15 revision; if your engine calls for Q15 or Q7, the Seachoice 50-21011 is the correct choice. Always confirm by engine model and serial number before ordering.
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.