Mercury – Water-Separating Fuel Filter | Fuel System Protection | Marine Coated Steel | 866594K01

Overview

Nothing spoils a perfect day on the water like contaminated fuel. Even when you purchase from reputable marinas, water and debris can still make their way into your tank. This is where the Mercury Marine part, number 866594K01, comes into play. This filter works quietly to protect your engine every time you turn the key. It keeps water out of the fuel system, safeguards the injectors from damage, and helps your engine run smoothly and steadily for those long outings you look forward to all week. When you rely on your boat as many of us do, having a reliable water separator makes all the difference.

Key Features

• Ten-micron element removes water and fine fuel contaminants.
• Internal epoxy coating protects against corrosion.
• Painted exterior resists rust and moisture exposure.
• Designed specifically for gasoline fuel.
• Built to Mercury Marine OEM filtration standards.

Engine & Boat Compatibility

• Fits MerCruiser 1.6L Vazer and 3.0L MPI EC sterndrive engines.
• Compatible with runabouts, sport boats, tow boats, and smaller cruisers.
• Works in freshwater and saltwater environments.
• Ideal for boats exposed to varying fuel quality.

Performance & Practical Benefits

This filter makes a noticeable difference in how reliably your engine runs. By capturing water before it reaches the fuel system, it protects injectors and prevents corrosion inside sensitive components. The engine idles smoother, starts more consistently, and maintains strong performance even when the conditions aren’t perfect.

The ten-micron element strikes the right balance — it is fine enough to trap damaging contaminants, but open enough to maintain proper flow under high demand. The internal epoxy coating is a thoughtful touch, reducing the risk of internal rust flaking into the fuel system. You can tell the filter was designed specifically for marine use, not repurposed from an automotive part.

Why Buy OEM

When it comes to fuel filtration, choosing generic options can have serious consequences. Mercury designs its water-separating filters to withstand marine moisture, fuel vibrations, and long-term exposure to harsh conditions. This attention to detail results in greater reliability, which translates to cleaner injectors, smoother throttle response, and fewer issues overall. If you want to ensure consistent performance and peace of mind, opting for OEM filters is the best choice.

FAQ

Q1: What engines does this filter support?

It fits MerCruiser 1.6L Vazer and 3.0L MPI EC engines.

Q2: What makes OEM better for water-separating filters?

More effective water removal, stronger materials, and corrosion-resistant construction.

Q3: How do I confirm it’s the correct filter?

Match your engine model and confirm it uses a ten-micron Mercury filter.

Q4: Is it good for saltwater running?

Absolutely — it’s designed to withstand high humidity and corrosion.

Q5: Is installation straightforward?

Yes, with a standard filter wrench and basic fuel-system safety practices.