In-Line Fuel Filter – Fits Mercury & Mariner 30–400HP 4-Stroke (Replaces 35-879885Q)
In-Line Fuel Filter – Fits Mercury & Mariner 30–400HP 4-Stroke (Replaces 35-879885Q) 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).
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Delivery and Shipping
Delivery and Shipping
Free standard shipping on all orders under 1 KG
In-Line Fuel Filter – Fits Mercury & Mariner 30–400HP 4-Stroke ...
Product Details
This high-quality Mercury In-Line Fuel Filter is designed for a wide range of Mercury and Mariner 4-stroke outboard engines from 2004 and newer, including 30–40 HP EFI, 40–60 HP (996cc), 75–115 HP (1.7L), and 135–400 HP Verado models. It ensures your engine is protected from fuel contaminants for optimal performance.
This filter is a direct replacement for Mercury part numbers 35-879885Q, 35-879885T, 35-879885K, and Sierra 18-7718.
- Easy under-cowl, in-line installation.
- Provides 20-micron filtration for gasoline fuel systems.
- Features a translucent body with a flow direction arrow for correct setup.
Part Number Matrix
Use this matrix to confirm equivalent references across OEM and aftermarket.
| Brand | Part Number |
|---|---|
| Mercury | 35-879885Q |
| Mercury | 35-879885T |
| Mercury | 35-879885K |
| Sierra | 18-7718 |
Engine & Model Compatibility
Confirm your engine model/year in the table below.
Fits a range of Mercury & Mariner outboards and Mercury stern drives.
| Brand | Model | Rated HP | Stroke | Years | OEM Part No. | Notes |
|---|---|---|---|---|---|---|
| Mercury | 30-40 EFI FourStroke | 30–40 | 4-Stroke | 2004 and newer | 35-879885Q | 4 cylinder (996 cc) |
| Mercury | 40-50-60 EFI FourStroke | 40–60 | 4-Stroke | 2004 and newer | 35-879885Q | 4 cylinder (996 cc) |
| Mercury | 75-115 FourStroke | 75–115 | 4-Stroke | S/N 1B366823 & above | 35-879885Q | 1.7L models |
| Mercury | 75-115 FourStroke | 75–115 | 4-Stroke | S/N 2B094996 & up | 35-879885Q | 2.1L models |
| Mercury | 150 EFI FourStroke | 150 | 4-Stroke | S/N 1B905505 & above | 35-879885Q | |
| Mercury | Verado | 135–300 | 4-Stroke | 2004 and newer | 35-879885Q | |
| Mercury | Verado | 200–400 | 4-Stroke | 2004 and newer | 35-879885Q | L6 engine configuration |
Also compatible with the following Stern Drive models:
| Brand | Model | Notes |
|---|---|---|
| Mercury | Alpha One Stern Drive | |
| Mercury | R/MR Stern Drive | |
| Mercury | Vazer/Blackhawk Drive | |
| Mercury | 120/140 Stern Drive | 1.98 Ratio |
| Mercury | 165 Stern Drive | 1.65 Ratio |
| Mercury | 223/225-S Stern Drive | |
| Mercury | 470/485 Stern Drive | 1.84 RATIO |
| Mercury | 888/895 Stern Drive | 1.5 Ratio |
| Mercury | 1228 Stern Drive | 1.50 Ratio |
| Mercury | 1250 Stern Drive | 1.32 Ratio |
Technical Specs
- Product Type
- Inline Fuel Filter
- Installation
- Under cowl, in-line
- Filtration Rating
- 20 Micron
- Fuel Type
- Gasoline
- Connection
- 5/16" (7.9mm) fuel line
- Housing Material
- Plastic
- Housing Color
- Translucent
- Fitting Type
- Barbed
- Other Technical Attributes
- Flow direction arrow on housing
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 allow it to cool completely. For added safety, disconnect the battery.
- Locate the existing in-line fuel filter under the engine cowl. Note the direction of the flow arrow printed on the old filter.
- Place an absorbent rag or container under the filter to catch any spilled fuel.
- Carefully loosen the hose clamps and disconnect the fuel lines from both ends of the filter.
- Position the new filter, making sure the flow arrow points in the same direction as the original (towards the engine).
- Securely reconnect the fuel lines and tighten the clamps. Ensure they are snug but do not overtighten.
- Prime the fuel system according to your engine manufacturer's instructions.
- Start the engine and carefully inspect the filter and connections for any signs of leaks.
Troubleshooting & FAQ
How do I know if this filter fits my specific engine model?
This filter fits a wide range of Mercury/Mariner 4-stroke outboards and some stern drives. Please review the 'Engine & Model Compatibility' tables and match your engine's model, horsepower, and serial number range (if applicable). Comparing the part number (35-879885Q) to your service manual is the best way to ensure a perfect match.
What are the signs of a clogged or failing fuel filter?
Common symptoms include the engine hesitating or stalling, difficulty starting, rough idling, reduced power, and decreased fuel efficiency. If you notice any of these issues, a blocked fuel filter is a likely cause.
How often should this fuel filter be replaced?
It's recommended to replace your in-line fuel filter annually or every 100 hours of operation, whichever comes first. Refer to your engine's service manual for the precise maintenance schedule.
Is the micron rating of this filter the same as the OEM part?
Yes, this aftermarket filter is rated at 20 microns, which meets the specification for the OEM Mercury 35-879885Q filter, ensuring proper filtration and protection for your fuel injectors and engine components.
axDoes the installation direction matter?
Absolutely. Fuel must flow through the filter in a specific direction. The housing is clearly marked with an arrow indicating the direction of flow. Installing it backward can restrict fuel delivery and damage the filter media.
Where is this filter typically located on the engine?
This is an in-line filter located under the engine cowl. You will find it spliced into the fuel line between the fuel tank and the engine's fuel rail or carburetor.
OEM vs. Aftermarket?
This listing is an aftermarket replacement (not OEM). Built to OEM-level specifications with comparable materials. Manufactured in an ISO 9002 facility, batch-inspected for consistency.
Shipping speed & cost
axWe ship worldwide quickly—typical transit 5–15 days. Standard shipping is free; expedited options appear at checkout where available.
Warranty & returns
Covered by a 1-year warranty against manufacturing defects under normal use. If issues arise, contact support with your order details. Returns are accepted within our standard window (unused & in original condition). See our 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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