Winter Storage and E-10 Gasoline

There is probably more misinformation about fuel than any other current boating topic. (See CY Dec 2012 for a review of decommissioning advice). Gasoline with ethyl alcohol added (E-10 nomenclature means there is 10 percent ethyl alcohol in the mix, the most common formulation for mid-grade gas) is actually a good fuel when temperatures drop as the alcohol will absorb quantities of water that enter fuel tanks. However, once the alcohol is saturated, water will remain a separated liquid that may make running difficult, if not impossible next season.

Leaving space in the tank is not advisable as the air that comes and goes will bring moisture into the tank, especially in warm and wet winter days. With a drop in temperature, the moisture will condense into the fuel mix. The best solution is top up all tanks, not to the absolute brim but just below to allow for expansion when the temperature warms.  

Adding a fuel stabilizer addresses another concern not related to alcohol. All fuels, gas or diesel, are a mixture of a number of organic compounds that change composition with age. After about four weeks fuel starts to change its composition and this process never stops. After a few months, neither fuel is suitable for any marine engine and must be discarded.

If a fuel is going to be stored for longer than one month, a fuel stabilizer can be a good addition. When topping up the tanks in fall, consider a well-known brand of fuel stabilizers. There are many on the market and boaters and mechanics all have their favourites.

For more information visit:
www.boatus.com/seaworthy/winter