Marine Fuel System Maintenance | Fuel Water Separators | Sonark Marine

Stop Water From Getting To Your Injectors

Modern marine fuel — especially ethanol-blended gasoline — pulls water out of the air and into your tank. That water sits in suspension until your fuel pickup grabs it, then sends it straight to your injectors or carburetors where it can stall, corrode, and ultimately destroy components that cost thousands to replace. A $30 fuel/water separator catches it before it gets there. Annual replacement is the cheapest engine insurance you can buy.

Why Boats Need Separators (Cars Don't)

Marine fuel systems sit unused for weeks at a time. Tanks vent to atmosphere — they're never sealed. The fuel/air interface in a half-empty tank breathes in humid air every time the temperature swings. Phase separation in ethanol fuel makes water settle to the bottom of the tank, exactly where the pickup tube draws from. Fuel filters alone won't stop water — you need a dedicated water separator with a sediment bowl that lets water settle out before fuel reaches the engine.

What Goes Wrong Without One

Hard starts and stalling — water in the fuel rail won't combust. Your engine cranks fine but won't catch, or starts then dies.

Injector damage — water erodes injector tips and corrodes the spray pattern. New injectors run $80-200 each.

Carburetor corrosion — older outboards with carbs are especially vulnerable. Once water gets into the float bowl, you're rebuilding the carb.

Fuel pump failure — high-pressure fuel pumps in modern EFI outboards are not designed to handle water. Pump replacement starts at $300.