Fuel Filter for Mercury/Mariner 30–60HP (EFI) & Verado 135–300HP – Replaces 35-879885T Short Description (BG):

This Mercury/Mariner fuel filter (35-879885T equivalent) offers reliable protection for a wide range of Mercury outboard engines – from small 30–60 HP 3- and 4-cylinder EFI motors up to the big supercharged Verado engines of 135–300 HP. Serving as a common filtration component for such diverse engines streamlines maintenance and parts stocking: the same filter model can be used across different boats and engines in your fleet.

Features and use cases:

• Broad application range (30 to 300 HP): The filter serves equally well on small outboards powering inflatable boats and fishing skiffs, as it does on high-horsepower Verado engines on speedboats and offshore vessels. For example, if you have a 60 HP motor on a 4–5 m boat and a 250 HP Verado on a 7–8 m boat, both engines can use this filter – a convenience when keeping spare parts on hand.
• OEM-level filtration quality (30 microns): With an approximate 30-micron rating, the filter removes common fuel contaminants – corrosion particles from the tank, fuel sediment, and fine debris. This protects the fuel pump and injectors from wear or clogging, especially over long hours of operation or when using fuel of questionable quality. By filtering out dirt and water, it helps maintain proper fuel flow and prevents engine knock or lean running conditions.
• Inline design for easy installation: The filter is a compact in-line capsule with hose barb input and output (standard 5/16" hose). It installs directly in the fuel line under the engine cowling – simply detach the hoses from the old filter and connect them to the new one, securing with clamps. No special tools or modifications are needed for this quick replacement.
• Improved engine performance: With a clean fuel supply, your engine starts more easily, idles smoothly, and reaches full RPM without hiccups. This is particularly important for high-performance Verado engines (which are supercharged) – clean fuel is critical for full power output and avoiding detonation. This filter helps ensure crisp acceleration and guards expensive components like the high-pressure fuel pump from damage.
• Preventive maintenance: Mercury recommends regular replacement of this inline filter – typically during the annual service or every 100 hours of engine operation (whichever comes first). Changing the filter is an inexpensive insurance against potential problems: a clogged filter can result in lean fuel mixture, engine overheating, or loss of power. Keeping a spare filter on board is a smart practice, especially for long trips, so you can quickly swap it in if you suspect fuel contamination.

By using this universal fuel filter, you’ll ensure reliable performance from your Mercury outboard, no matter its size. The product is an OEM-equivalent, which means you get the quality and fit of the original Mercury filter. Invest in a quality filter – it translates to less downtime for repairs and more time enjoying your boat with confidence in your engine’s reliability.