Sierra fuel water separator filter AMRS-18-7945 — 4.35" long 10-micron replacement, high-flow 90 GPH

The Sierra AMRS-18-7945 is a 4.35" long, 10-micron fuel water separator designed to protect fuel-injection marine engines by removing emulsified water and fine particles.

Keep fuel clean and fuel systems running smoothly with a compact, high-flow replacement element engineered for inboard and outboard engines. This Sierra long fuel/water separator is built to meet the needs of modern fuel-injected marine powerplants: high flow rate, fine filtration, and strong water-removal capability in a cartridge sized for common housings.

How does this filter remove water and contaminants?

The AMRS-18-7945 uses a 10-micron media optimized to separate emulsified water from gasoline and capture particles that can damage injectors and pumps. Its construction balances fine filtration with high throughput so it won't starve the engine while trapping debris and moisture.

• 10 micron media rated for fuel injection systems
• Removes over 99.8% of emulsified water from gasoline (typical performance)
• Over 90% efficiency at capturing 10-micron particles
• Flows at 90 GPH to support high-demand engines

Will this fit my existing fuel-water separator housing?

The AMRS-18-7945 is a long (4.35") replacement cartridge designed to match housings that accept the 18-7945 length and style. It cross-references several OEM part numbers, making it a drop-in option for many common marine filtration systems.

• Physical length: 4.35" (long cartridge)
• Direct replacement for Mercury 35-802893Q01 and other OEM codes
• Compatible with housings designed for long, 10-micron elements
• Check your housing gasket and sealing surface for a proper fit

How will this filter affect engine reliability and maintenance?

Regular use of a capable fuel/water separator like this one reduces the chance of injector fouling and fuel-pump wear by keeping water and particulates out of the fuel system. Because it maintains 90 GPH flow, it supports peak engine demand while protecting sensitive components.

• Recommended for protecting fuel injection systems from contaminants
• Helps prevent downtime linked to water-contaminated fuel
• Designed to feed even high-flow engines without restriction
• Periodic replacement keeps filtration performance consistent

Who is this for?

This Sierra AMRS-18-7945 filter is aimed at boat owners, mechanics, and fleet operators who run fuel-injected inboard or outboard engines and need a reliable, high-flow cartridge that removes water and fine particles. If your engine manufacturer or maintenance schedule calls for a 10-micron long cartridge, or if you need a replacement for Mercury 35-802893Q01, Yamaha ABB-FUELF-IL-TR, Mallory 9-37801, GLM 24940, OMC 0509532, Redline RL7844, Fram PS3808, or Tohatsu 3Y9022340, this Sierra element is a practical choice. Install during routine service intervals to maintain fuel system performance and reduce the risk of fuel-related failures.