Upgrade Your Outboard's Fuel System with the Sierra 18-7784 Fuel Filter

Keep your Mercury or Mariner outboard running smoothly on the water with the Sierra 18-7784 fuel filter cartridge. Designed as a direct replacement for OEM part number 35-8M0046752, this high-quality filter traps contaminants like dirt, rust, and debris that can clog injectors and disrupt performance. Boat owners trust Sierra parts for their reliability and exact-fit engineering, ensuring you spend less time troubleshooting and more time enjoying the ride.

Perfect Fit for Popular Mercury Outboards

The Sierra 18-7784 is compatible with a wide range of Mercury and Mariner four-stroke outboards, especially those with electronic fuel injection (EFI) systems from the mid-2000s onward. It slots right into models like the 75-300 HP Verados and Optimaxes, where clean fuel flow is critical for peak power and fuel efficiency. Always double-check your engine's service manual for exact compatibility to avoid any mismatches.

• Replaces Mercury OEM: 35-8M0046752
• Suits select 4-stroke EFI outboards (75-300 HP range)
• Cartridge-style design for easy inline installation

Key Features That Deliver Superior Filtration

What sets the Sierra 18-7784 apart? Its premium media captures particles as small as 10 microns, far better than basic filters that let grit through. Constructed with durable, corrosion-resistant materials built for harsh marine environments, it withstands ethanol-blended fuels without breaking down. You'll notice quicker throttle response and fewer hesitation issues after installation, thanks to unrestricted fuel delivery.

Simple Installation: DIY in Under 30 Minutes

Swapping out your old fuel filter doesn't require a marine mechanic. Here's a quick step-by-step:

1. Shut off fuel supply and relieve system pressure (use a rag to catch any spills).
2. Locate the inline filter housing on your fuel line, typically near the primer bulb or engine cowling.
3. Twist off the old cartridge counterclockwise and inspect for debris.
4. Insert the new Sierra 18-7784, ensuring O-rings are seated properly—lubricate with fuel if needed.
5. Reassemble, prime the system, and test run the engine.

Pro tip: Replace every 100 hours or annually, or sooner if you notice sputtering or hard starts.

Why Sierra Engine Parts Outperform the Rest

Sierra has built a reputation among boaters for OEM-level quality at a fraction of dealer costs. Backed by rigorous testing for flow rates, burst pressure, and filtration efficiency, the 18-7784 matches or exceeds Mercury specs. It's not just a filter—it's peace of mind against water intrusion or bad gas from the marina pump. Pair it with routine fuel separator checks for a bulletproof fuel system.

Frequently Asked Questions