Quicksilver Blog

How to Check For Water in Fuel

Gasoline blended with up to 10 percent ethanol (E10) is common at gas pumps in many parts of the country. According to some estimates, E10 represents about 50 percent of the gasoline sold in the U.S. Most modern engines are designed to run on E10, and the small amount of ethanol it contains usually won’t pose any problem for the general performance of your boat, motorcycle or ATV. However, ethanol-blended fuel can cause other problems for powersports equipment.

Phase Separation

One property of ethanol is that it is hygroscopic, meaning it absorbs moisture from the air. This can create big problems, especially for equipment that sits unused for long periods of time. The ethanol in gasoline attracts and absorbs water either from the fuel source or from condensation that forms inside the fuel tank. In time, it’s possible for the ethanol to absorb enough moisture that water, which is heavier than gasoline, will drop to the bottom of the fuel tank. This is called phase separation. If this water/ethanol phase reaches the fuel inlet it can either clog up the small orifices in carburetors or be drawn into the engine and cause poor performance or even damage.

How to Check for Water in Fuel

If you suspect that water has contaminated your fuel supply, there are two ways to check for the presence of water or phase separation.

The simplest method is to siphon or drain a few ounces of fuel into a clear glass container and let it sit for about 30 minutes to allow the fuel to settle. Because water is denser than gasoline, it will form a clear bubble or layer at the bottom of the container. Phase separation will be evident by the formation of an opaque, gelatinous layer below the gasoline.

Another method is to apply water-finding paste to a wooden stick or dowel and submerge it down to the bottom of the fuel tank. The paste will change color in the presence of water, indicating contamination.

If either method results in a positive test for water in the fuel, your best course of action is to completely drain the fuel tank and refill it with fresh fuel.

Preventing Fuel Problems

The fuel in your vehicle requires special care to keep your engine running at peak performance. In as little as two weeks, fuel components can begin to oxidize, forming a gum-like substance that settles in fuel lines and tanks, carburetors and fuel injectors. When the engine tries to burn this fuel, deposits can form in the combustion chamber. Over time, these deposits build up and reduce the engine’s performance. Engines with carburetors are especially prone to problems caused by these deposits, which can clog small jets and passages in the carburetor. Fuel treatments won’t remove water that has already contaminated your fuel, but they can help prevent it from occurring.

Quicksilver® Fuel Care System additives are formulated to keep your fuel optimized, protect your fuel system and prevent these harmful deposits from forming. Each additive is highly concentrated for convenient use in large-capacity fuel tanks. Follow the instructions on each product to ensure maximum protection.

Quicksilver Quickare® Fuel Treatment

Use this complete fuel treatment when you fill your tank with new fuel. Quickare maximizes engine performance with all grades of gasoline.

  • Helps prevent corrosion, gum and varnish build-up.
  • Helps control moisture and corrosion problems associated with ethanol-blended fuel.
  • Cleans existing varnish and gum deposits from fuel lines, tanks, carburetors and injectors, intake valves, and spark plugs.

Quicksilver Quickleen® Engine and Fuel System Cleaner

Use this deep-cleaning fuel treatment periodically during the boating season. Quickleen contains aggressive cleaners that quickly and thoroughly remove carbon deposits from carburetors and injectors, intake valves, spark plugs, piston crowns and cylinder heads.

  • Prevents engine knocking and piston seize-up.
  • Extends spark plug life.

Quicksilver Quickstor® Fuel Stabilizer

Use this additive before short- or long-term (off-season) storage. Quickstor stabilizes fuel for up to a year and keeps fuel ready for use when it’s time to put your equipment back in service. For best results, always treat fresh fuel before storage.

  • Helps prevent regular and ethanol-blended fuel from breaking down and oxidizing.
  • Reduces fuel system corrosion.
  • Helps keep gum and varnish from forming in the fuel and settling in fuel lines and tanks, carburetors and injectors.
  • Keeps injectors and carburetors lubricated.

More Fuel Care Tips

Quicksilver recommends following these additional precautions to avoid fuel-related problems:

  • Buy gas from known and trusted sources whenever possible. A busy filling station is likely to dispense fresh fuel.
  • Use ethanol-free fuel if available.
  • Keep your fuel tank clean and check it periodically for water and sediment.
  • Check your fuel filter often. Fuel filters help prevent fuel contaminants from entering your engine.
  • For marine applications, consider installing a water-separating fuel filter. Some filters are also available with a water-sensing alarm feature.
  • Fuel tanks that are vented to the atmosphere should be kept filled when stored for long periods of time to reduce the chance of condensation forming in the tank. Non-vented fuel tanks can be safely stored with a lower fuel level.
  • The actual percentage of ethanol in gasoline rated as E10 can vary. If you are wondering how much ethanol your fuel actually contains, use a tool such as the Quicksilver Fuel Tester (PN 91-879172T28) to accurately measure the percentage of ethanol in your fuel.

Whether or not you run ethanol-blended fuel, following these fuel care tips can help ensure problems with bad gas don’t spoil a great day outdoors.