100% Gas or Ethanol Fuel for your Boat and Jet Ski.

Battle of the Fuels at the Pump.
Seems everyone has a different opinion or answer for recommended fuel for marine use. The majority of watercraft we get into the shop have degraded fuel. How often do people check the fuel in there Waverunner or Sea-doo? Never. “fuel is used and fresh gas is put in every time” is the assumption. Unfortunately, no Watercraft can be completely drained of gas without removing the gas tank or physically removing the gas. All watercraft have a sending unit “gas pickup” that extends to the bottom of the tank. Most of the time this is near the bottom or an inch or 2 from the bottom. If the bottom layer of gas is contaminated, The new gas is mixed with the contaminated gas while filling up.

Phase Separation
Phase separation is the separation of water and ethanol from fuel within a tank. When water is present in a tank, it bonds to the ethanol molecules in the fuel. Once the three-part mixture of water, ethanol, and fuel reach a certain point, the ethanol and water will drop to the bottom of the tank and separate from the fuel. Once this occurs, you are in danger of severely damaging your motor. Depending on where your fuel inlet is located, your motor might receive the fuel portion of what is in the tank or the ethanol/water mixture. Both will cause problems with your motor. While the water/ethanol mixture will obviously cause damages, the fuel portion will be stripped of octane and leads to engine knock and further damage.

Winter storage of ethanol-blended gas
Seasonal storage with E10 fuel is another likely time for problems. During storage, fuel will tend to oxidize; it will become “sour”, and may absorb water from condensation. Water-holding capacity of E10 fuel is reduced with lower temperatures, so phase separation is more likely with winter temperatures. E10 can hold approximately 0.5% water at 60°F (.64 ounces in a gallon, or 12 ounces of water in a 20-gallon gas tank), but can only hold about 0.35% water at 20°F (.45 ounces in a gallon).
If possible, store your boat for the winter with a full fuel tank. Add a fuel stabilizer to the fuel at the recommended dosage. Run the engine for 10 minutes to distribute stabilized fuel into the engine and fuel lines. Top off the tank to reduce the amount of exchange with the air that may bring in condensation. Note: Some storage facilities require that fuel tanks be empty for storage.
Leave A Comment
You must be logged in to post a comment.