In-Line Fuel Filter – Fits Mercury/Mariner 30-350 HP 4-Stroke (Replaces 35-879885Q, 35-879885T, 35-879885K)
In-Line Fuel Filter – Fits Mercury/Mariner 30-350 HP 4-Stroke (Replaces 35-879885Q, 35-879885T, 35-879885K) is backordered and will ship as soon as it is back in stock.
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Worry-free returns
Worry-free returns
You may return most new, unopened items within 7 days of delivery for a full refund. We'll also pay the return shipping costs if the return is a result of our error (you received an incorrect or defective item, etc.).
You should expect to receive your refund within four weeks of giving your package to the return shipper, however, in many cases you will receive a refund more quickly. This time period includes the transit time for us to receive your return from the shipper (5 to 10 business days), the time it takes us to process your return once we receive it (3 to 5 business days), and the time it takes your bank to process our refund request (5 to 10 business days).
If you need to return an item, simply login to your account, view the order using the "Complete Orders" link under the My Account menu and click the Return Item(s) button. We'll notify you via e-mail of your refund once we've received and processed the returned item.
Delivery and Shipping
Delivery and Shipping
Free standard shipping on all orders under 1 KG
In-Line Fuel Filter – Fits Mercury/Mariner 30-350 HP 4-Stroke (Repl...
Product Details
This In-Line Fuel Filter is engineered for Mercury and Mariner 4-stroke outboard engines ranging from 30 to 350 HP, including EFI, Verado, and Pro Verado models manufactured from 1996 and newer. It provides essential protection by removing contaminants from the fuel system before they can reach the engine, ensuring reliable performance.
Serves as a direct interchange for Mercury part numbers 35-879885Q, 35-879885T, and 35-879885K, along with Sierra 18-7718 and select Yamaha equivalents. Its design ensures a precise fit for under-cowl installation.
- Installs under the cowl, in-line with the existing 5/16" (8mm) fuel hose.
- Approved for use with gasoline and ethanol-blended fuels like E10.
- Features sonically sealed end caps to prevent leaks and ensure durability.
Part Number Matrix
Use this matrix to confirm equivalent references across OEM and aftermarket.
| Brand | Part Number | Notes |
|---|---|---|
| Mercury | 35-879885Q | OEM Reference |
| Mercury | 35-879885T | OEM Reference |
| Mercury | 35-879885K | OEM Reference |
| Mercury | 879885Q | OEM Reference |
| Sierra | 18-7718 | Aftermarket Interchange |
| Yamaha | 6G1-13621-A1-00 | Cross-reference only |
| Yamaha | 6G1-13621-00-00 | Cross-reference only |
Engine & Model Compatibility
Confirm your engine model/year in the table below.
For Mercury and Mariner models, fitment may be defined by a serial number (S/N) range. Please verify your engine's serial number to ensure correct application.
For Yamaha models, this part is provided as a cross-reference. Please verify fitment against your specific engine's requirements, as application details are limited.
| Brand | Model | Rated HP | Stroke | Years | OEM Part No. | Notes |
|---|---|---|---|---|---|---|
| Mercury | EFI FourStroke | 30, 40 | 4-Stroke | 1996 and newer | 35-879885Q/T/K | Under-cowl installation |
| Mercury | FourStroke (996cc) | 40, 50, 60 | 4-Stroke | 1996 and newer | 35-879885Q/T/K | 4-cylinder models |
| Mercury | FourStroke 1.7L | 75–115 | 4-Stroke | S/N 1B366823–2B094995 | 35-879885Q/T/K | |
| Mercury | FourStroke 2.1L | 75–115 | 4-Stroke | S/N 2B094996 and above | 35-879885Q/T/K | |
| Mercury | EFI FourStroke | 150 | 4-Stroke | S/N 1B905505 and above | 35-879885Q/T/K | |
| Mercury | Verado | 135–300 | 4-Stroke | 2004 and newer | 35-879885Q/T/K | |
| Mercury | Pro Verado | 200, 250, 300 | 4-Stroke | 2004 and newer | 35-879885Q/T/K | 6-cylinder |
| Mercury | Pro Verado | 350, 400R | 4-Stroke | 2015 and newer | 35-879885Q/T/K | 6-cylinder |
| Mariner | Outboards | 30–300 | 4-Stroke | 1996 and newer | 35-879885Q/T/K | |
| Yamaha | 6C/6D/6MH/6CMH/6DMH/6TRV | 2-Stroke | 1984 and newer | 6G1-13621-00-00 | Cross-reference only |
Technical Specs
- Product Type
- In-Line Fuel Filter
- Installation
- Under-cowl, in-line with fuel hose
- Filtration Rating
- 20–30 micron
- Fuel Type
- Gasoline, ethanol blends (e.g., E10)
- Connection
- 5/16" (8mm) fuel line
- Fitting Type
- Push-on barb connection
- Housing Material
- Translucent plastic
- Housing Color
- Clear
- Dimensions
- 4.8" × 4.6" × 7.4" (122 × 117 × 188 mm)
- Weight
- 0.2 lb (0.09 kg)
- Warranty
- 1-year against manufacturing defects (aftermarket)
- Other Attributes
- Sonically sealed end caps; approved for use with ethanol-based fuels
What’s in the Box
- 1 x In-Line Fuel Filter (replaces 35-879885Q/35-879885T/35-879885K)
Installation Notes
- Turn off the engine and disconnect the battery.
- Locate the existing fuel filter under the engine cowl.
- Place a rag beneath the filter to catch any spilled fuel.
- Carefully loosen the hose clamps on both sides of the filter.
- Twist and pull the fuel lines off the old filter. Note the direction of the fuel flow arrow.
- Position the new filter, ensuring the arrow on the housing points in the same direction of fuel flow.
- Slide the fuel lines completely onto the new filter barbs.
- Secure the lines by tightening the hose clamps.
- Reconnect the battery.
- Prime the fuel system according to your engine's manual and check thoroughly for leaks before starting the engine.
Troubleshooting & FAQ
How do I know if this filter fits my specific engine model?
The best way to confirm is by checking our compatibility table. Many Mercury and Mariner models use serial numbers (S/N) instead of calendar years for identification. Compare the part numbers listed in your engine’s service manual with our Part Number Matrix. If you are still unsure, contact us with your engine's make, model, year, and serial number before ordering.
How often should I replace my in-line fuel filter?
For general preventative maintenance, it is best practice to replace your fuel filter annually or every 100 hours of operation, whichever comes first. If you frequently use fuel with higher ethanol content or notice performance issues, more frequent changes may be necessary.
What are the signs of a clogged or failing fuel filter?
Common symptoms include difficulty starting the engine, rough idling, engine stalling at low speeds, hesitation during acceleration, and an overall loss of engine power. The clear housing on this filter also allows for visual inspection of trapped debris.
Is this filter compatible with ethanol-blended fuels?
Yes, this filter is designed and approved for use with modern gasoline, including ethanol blends up to E10. The materials are resistant to the corrosive effects of ethanol.
What is the difference between an OEM part and this aftermarket filter?
This is an aftermarket part designed to meet or exceed original equipment manufacturer (OEM) specifications for fit, form, and function. It offers comparable performance and filtration at a better value, but it is not manufactured or branded by Mercury Marine.
How fast is shipping and what does it cost?
We ship worldwide quickly—typical transit is 5–15 days. Standard shipping is free to most locations, and expedited options may be available at checkout depending on your address.
What is the warranty and return policy?
This part is covered by a 1-year warranty against manufacturing defects under normal use. If you encounter an issue, please contact our support team with your order details. Returns are accepted within our standard window for items that are unused and in their original condition. See our full policy page or reach out for instructions.
Safety & Important Info
- Verify images/specifications vs your original part. If anything differs—even if your model appears compatible—do not purchase.
- This is an aftermarket replacement, not an OEM component.
- Professional installation is recommended for safety and performance.
About Sea Sierra
- Pro-Grade Standards — We supply marine parts engineered to OEM-level tolerances and tested for real-world conditions.
- Fast Global Fulfillment — Free standard delivery to most regions in 5–15 days.
- Manufacturer-Direct Value — Fair pricing without compromising on materials or QC.
Payment & Security
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