35-879885K 35-879885Q 35-879885T Fuel Filter for Mercury | JLM Marine

Fuel Filter – Fits Mercury 4-Stroke Outboards 40–300 HP

This aftermarket fuel filter is engineered for Mercury 4-stroke outboards ranging from 40 HP to 300 HP. Designed to replace OEM part numbers 35-879885K, 35-879885Q, and 35-879885T, it ensures reliable fuel filtration for your marine engine.

Built to OEM specifications, this filter provides direct fitment for Mercury Mariner outboard models, helping maintain clean fuel flow and engine performance across a wide horsepower range.

• Fuel line connection: 8mm (5/16 inch)
• Compatible with Mercury 4-stroke outboards from 40 HP to 300 HP
• Direct replacement for multiple Mercury OEM part numbers

Part Number Cross-Reference

Use this table to confirm equivalent part numbers across OEM and aftermarket brands.

Compatible Engine Models

Confirm your engine model/year in the table below. For Mercury owners, here's a guide to help you identify your engine's serial/model: Mercury Serial Number Guide. You can also review exploded diagrams to verify part numbers: Mercury Parts Diagrams & Catalog.

Technical Specifications

Package Contents

Your package includes:

• 1 × Fuel Filter

Installation Guide

1. Disconnect the battery and ensure the ignition is off. Relieve fuel system pressure before proceeding.
2. Locate the existing fuel filter on your Mercury outboard, typically along the fuel line between the tank and engine.
3. Use pliers or a wrench to loosen the hose clamps on both sides of the old filter. Have a rag ready to catch any residual fuel.
4. Carefully slide the fuel hoses off the old filter and remove it from the system.
5. Inspect the fuel hoses for cracks or damage; replace if necessary.
6. Note the direction of fuel flow (usually indicated by an arrow on the filter body). Install the new filter with the arrow pointing toward the engine.
7. Slide the fuel hoses onto the inlet and outlet fittings of the new filter, ensuring a snug fit over the 8mm (5/16 inch) barbs.
8. Secure both hose connections with new or existing hose clamps, tightening them firmly.
9. Double-check all connections for proper seating and clamp tightness.
10. Reconnect the battery and prime the fuel system by squeezing the primer bulb until firm.
11. Start the engine and inspect the filter area for any fuel leaks. Address any leaks immediately.
12. Run the engine for a few minutes at idle, then check all connections again to ensure secure installation.

Troubleshooting & FAQ

Q: How do I confirm this fuel filter fits my Mercury outboard?
A: Check that your engine is a Mercury or Mariner 4-stroke model rated between 40 HP and 300 HP, and verify your original filter uses an 8mm (5/16 inch) fuel line connection. Cross-reference the OEM part numbers 35-879885K, 35-879885Q, or 35-879885T with your service manual or parts diagram.

Q: How often should I replace my fuel filter?
A: Mercury recommends inspecting the fuel filter every 100 hours of operation or annually, whichever comes first. Replace it if you notice reduced performance, hard starting, or visible contamination inside the filter housing.

Q: What are the signs of a clogged or failing fuel filter?
A: Common symptoms include engine hesitation, rough idling, stalling under load, difficulty starting, or loss of power at higher RPMs. If you experience these issues, inspect and replace the fuel filter as part of your troubleshooting process.

Q: Can I install this filter in either direction?
A: No. Always install the filter with the flow arrow pointing toward the engine (away from the fuel tank). Incorrect orientation can restrict fuel flow and cause engine performance issues.

Q: What's the difference between OEM and aftermarket fuel filters?
A: This listing is an aftermarket replacement part (not an OEM component). We build to OEM specifications using comparable-grade materials. Production is done in an ISO9002-certified facility, and each batch is inspected for consistent performance.

Q: How fast do you ship and how much does it cost?
A: We offer fast global shipping—typically 5–15 days worldwide—and standard shipping is free. Expedited options are available at checkout depending on your location.

Q: What is your warranty and return policy?
A: This product includes a 1-year warranty against manufacturing defects under normal use. If something goes wrong, contact our support team with your order details. Returns are accepted within our standard return window (unused & in original condition); please see our policy page or reach out for instructions.

Important Notes

• Verify that the product images and specifications match your original part. If discrepancies exist—even if your model is listed—do not proceed with the purchase.
• This product is an aftermarket replacement part and is not an OEM component.
• Professional installation is recommended to ensure safety and optimal performance.

Why Choose JLM MARINE?

• Quality Assured: As a trusted manufacturer for over 20 years, we supply top marine brands globally.
• Fast Global Shipping: Free delivery worldwide in 5–15 days.
• Direct from Manufacturer: Competitive pricing without compromising quality.