Ethanol fuels can be a real nightmare to boat owners. Ethanol poses 3 problems for boat owners. 1. It acts as a “cleaning agent”. That means the ethanol will loosen any dirt or debris in the tanker truck that hauls it, the gas station tank that stores it and your gas tank. This suspended gunk will then flow thru your fuel system and can clog your fuel lines, carburetors or fuel injectors and fuel filters. 2. Ethanol absorbs/attracts water. Just sitting in your gas tank, the ethanol can draw in water from the outside air. This can be especially bad at dock side “gas stations”. The water will also cause “phase separation”. That means the fuel/water mixture will separate with the water going to the bottom of your tank….where your fuel pickup is, resulting in a deadly gulp of water and then alcohol before the actual fuel can make it to your power head. This causes poor running, engines dying and falling off plane and piston detonation. This also causes the shelf life of your gas to decrease to around 20 days. 3. Ethanol does not mix well with the other blends of gas (MTBU). If you should accidentally mix the 2 blends of fuel (use half a tank of gas and then top it off with another blend) the fuels will form a coagulated mixture that can clog your fuel system to the point that the entire carb and fuel lines will have to be replaced. A 50/50 mixture is the deadliest.
- Nothing is an absolute cure. To lessen the effects, use a fuel conditioner as discussed in item II Carbon Buildup. This will inhibit the water absorption and prolong the life of the fuel. Put a 10-micron fuel filter/water separator in the fuel line. This will help keep the tiny suspended debris out of your injectors/carbs and take the water out BEFORE it hits the power head. Change your filter at least once a year and keep an extra onboard in case you get water in your fuel. Periodically pour out the contents of your filter into a glass container to inspect your system for any water or debris. Avoid refilling a half full tank with fresh gas….or make sure it is the same type you put in before.