Winterizing Your Boats Fuel System 7

Most of the gasoline blends you'll find nowadays contain an additive called E10 (Ethanol) that only has as shelf life about 45 to 60 days. If your boat is operated thru the winter months and you're keeping fresh fuel in it constantly the E10 shouldn't cause too many problems. If steps aren't taken to properly store fuel in boats layed up for the winter, however, water can form in the tank and cause major problems. Boats work great on the water, but water doesn't work great in the engines we use on them.

Ethanol is grain alcohol that's produced from crops like corn, sorghum, wheat, and rice and it's used as an “oxygenate" to reduce exhaust emissions by introducing additional oxygen molecules to the combustion process. Ethanol has largely replaced another fuel additive, MTBE, in gasoline supplies in urban areas and is appearing more frequently in fuel supplies in rural areas.

If your boat sits for longer than 45 to 60 days the fuel and ethanol will start to go their seperate ways. Ethanol actually absorbs water about ten times more than regular gasoline and when it settles to the bottom of the tank it brings the water with it. The bottom of the fuel tank is exactly where the fuel pickup is for most inboard and outboard engines. This process is called "phase seperation" and it's bad mojo for any marine engine.

A fuel/water seperator is the first line of defense, but if there's too much water in the tank it can easily fill the capacity of the filter and end up in the engine. By that time it's too late. If phase seperation has occured the only thing to do is have the tank pumped dry and start over with a fresh tank of fuel. Bring your boat to an approved marine service facility to have this done.

Ethanol can also act as a corrosive agent on aluminum fuel tanks if it isn't stabilized properly. When it's allowed to phase seperate from the fuel blend over the winter the E10 that settles to the bottom of the tank can oxidize the aluminum, causing minute flaking of the tank that can clog up the fuel filter. It also strips away any varnish or "gumming" in the tank, all of which ends up in the fuel filters.  

What can you do?
The best way to store a boat for the winter is to fill the gas tank to it's capacity and use a fuel stabilizer like Star Tron or Sta Bil that keeps the fuel fresh during storage. The stabilizer should be added to the gas tank prior to filling so that thorough mixing occurs and then if possible run the engine for ten to fifteen minutes, or even longer, to allow the stabilizer to pass thru the entire fuel system. This keeps small amounts of water from forming in the engines fuel lines and filters.

Larry Carpenter, owner of Master Marine Services in Mount Vernon, Washington likes to use Star Tron fuel stabilizer manufactured by Star Brite. "It contains enzymes that keep ethanol and water from chemically bonding together and it also breaks down any debris that forms in the fuel tank," says Carpenter of his choice in a fuel stabilizer.

Keeping the tank full during storage reduces the fuels exposure to moist air and water vapor. When temperatures fluctuate greatly in the fall and spring a large quantity of air in the gas tank can expand and draw moist air into the tank. Filling your boats fuel tank and thus reducing the air space within the tank will reduce the chance of this occuring.

It's also important to check the gasket on the tanks gas cap for damage, as damage to this gasket can allow rainwater to enter the tank from above.

If possible park the boat in a shaded area to reduce the severity of temperature swings that cause moist air to vent into and out of the tank. The vent should be left open and unplugged so that the tank can breath adequately.

Taking these steps can ensure a long life for your marine engine and you'll have a full tank of gas when you pull the boat out next spring.

Action Alert: The EPA is about to make a critical decision to increase Ethanol content in fuel from 10% to 15%. This could have catastrophic consequences for the companies that manufacture marine engines. Click on this LINK to email the EPA and tell them to hold off on approving an increase in Ethanol until more research is done. http://www.boatus.com/gov/  

Rob Endsley
The Outdoor Line
710 ESPN Seattle
www.theoutdoorline.com