Seachoice 50-21018 Full-Flow Oil Filter – 20 Micron | Yamaha 4-Stroke Outboard
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Seachoice 50-21018 Full-Flow Oil Filter – 20 Micron
Part Number: 50-21018 Â |Â SKU: 50-21018 Â |Â UPC: 719249210186
The Seachoice 50-21018 is a 20-micron full-flow spin-on oil filter for selected Yamaha 4-stroke outboard engines, specifically those using the 3FV and 3FC filter thread series. It crosses directly to Sierra 18-7902 and to six Yamaha OEM filter revisions across the 3FV-13440 and 3FC-13440 families. Built with a high-efficiency cellulose element, anti-drain-back valve, epoxy-coated canister, reinforced body, and heavy-duty end-cap seals, it meets or exceeds original equipment filtration requirements.
Key Specifications
- Filtration: 20 micron
- Filter type: Full-flow spin-on
- Thread: 20 mm x 1.5
- Filter media: High-efficiency cellulose
- Anti-drain-back valve: Yes
- Canister: Epoxy-coated steel for corrosion resistance
- Body: Reinforced construction
- End-cap seals: Heavy-duty
- Manufactured in an ISO/TS 16949 certified facility
Compatible Applications
- Yamaha F9.9C / FT9.9D — selected years
- Yamaha F15A — selected years
- Yamaha F20A — selected years
- Yamaha F25A — selected years
- Yamaha F40A / F40B — selected years
- Yamaha F50A / FT50B — selected years
- Yamaha F80A and F100A — selected applications
- Other Yamaha 4-stroke outboards specifying a 3FV-13440 or 3FC-13440 series oil filter
Fitment Note: Confirm your Yamaha model, year, and existing OEM filter number before ordering. The 20 mm x 1.5 thread is specific to this filter family and differs from other Yamaha 4-stroke filters that may look similar. Exact model year coverage varies — matching a 3FV-13440 or 3FC-13440 series part number is the most reliable confirmation.
Service Interval
Replace at every scheduled engine oil service, following Yamaha’s recommended service interval — typically every 100 hours or once per season, whichever comes first.
Installation Notes
- Remove the old filter and confirm the old gasket has come away with it — a retained gasket will cause an oil leak
- Clean the filter mounting surface
- Lightly coat the new filter gasket with fresh engine oil before threading it on
- Tighten by hand plus ¾ turn, or per Yamaha service specification — do not over-tighten
- Run the engine and inspect for leaks before returning to service
Cross-Reference Part Numbers
- Seachoice: 50-21018 / 21018
- Sierra: 18-7902
- Yamaha: 3FV-13440-00-00, 3FV-13440-10-00, 3FV-13440-20-00, 3FV-13440-30-00
- Yamaha: 3FC-13440-20-00, 3FC-13440-30-00
Related Products
- Sierra 7902 4-Cycle Outboard Oil Filter — OEM-equivalent Sierra filter this unit replaces
- Seachoice 50-21011 Full-Flow Oil Filter – 20 Micron — Mercury & Yamaha 69J-series outboard filter
- Seachoice 50-21001 Full-Flow Oil Filter – 20 Micron — MerCruiser, OMC & Volvo Penta sterndrive filter
Parts Desk Insights
Best Use Case: Routine oil changes on Yamaha F-series 4-stroke outboards in the 9.9 to 100 HP range that use the 3FV or 3FC filter thread. This is a common filter for mid-range Yamaha outboards produced from the late 1990s through the 2000s. The six Yamaha OEM part numbers in the 3FV and 3FC series all represent successive production revisions of the same filter, and this Seachoice unit covers all of them.
Common Issues: Yamaha uses multiple oil filter threads across its 4-stroke outboard lineup, and several of them look nearly identical. Always confirm by matching a 3FV-13440 or 3FC-13440 Yamaha part number, or the Sierra 18-7902 cross-reference, rather than ordering by appearance or physical size alone. The 20 mm x 1.5 thread spec is the clearest technical differentiator from other Yamaha filter families.
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.
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