Maintenance of powerboat fuel system

One of the important reason why we have to do maintenance on our boat is impact of the fuel used. The advent of E10 gasoline (gas with 10 percent ethanol) has caused major problems for boaters. The fuel dissolves some fiberglass fuel tanks and can attack hoses and seals on older boats. The stuff that it dissolves may end up clogging your carburetor or injectors. The fuel itself deteriorates much faster, too, because it can attract fifty times more water vapor from the atmosphere than conventional gasoline. When too much water is absorbed, a phenomenon called phase separation occurs, in which the water and ethanol drop to the bottom of the tank and the gas floats to the top, losing about three points of octane in the process. Needless to say, you can’t burn the water rich stuff on the bottom, and the reduced-octane gas on top isn’t much good either. The bottom line is that boaters should inspect their fuel systems annually and be prepared to spend more time on fuel system maintenance than ever before.

Gasoline is dangerous to work around, so before we get started, let’s review a few safety tips: Have a Class B fire extinguisher rated for flammable liquids close at hand. Turn off the boat’s electrical system at the batteries. It should go without saying that while working on your fuel system or while pumping fuel you should not smoke or use any tools that create sparks, including most electrical power tools. When gawkers come by to visit, make sure they observe the rules. At the same time, take appropriate steps to avoid polluting the water either directly or through groundwater runoff. If you put so much as a light sheen of oil on the water, you may be liable for stiff Coast Guard pollution fines. When draining a fuel system, have plenty of absorbent pads to catch drips. Check with your marina or municipal authorities about the proper disposal of used oil and bad gas.
Here’s what you can do to maintain the health of your fuel system:

• Inspect. All hoses should be regularly checked for brittleness, cracks, or softening. If you detect changes in your fuel lines, change them earlier rather than later. A soft hose indicates that the interior structure is deteriorating and could delaminate and completely plug the fuel line.
• Replace. Replacement fuel line should be purchased at a marine store, not an auto parts store. There are three types of fuel line in common use, and all three need to have the appropriate USCG (U.S. Coast Guard) and SAE (Society of Automotive Engineers) certification notices printed on the hose itself. Type A1 hose is black and is used for fuel and vent lines. Type A2 hose is also black and is used for fuel fill lines. Type B1 fuel lines are gray and are used with outboard fuel systems. Measure all the lines you need to replace before you go to the marine store, and allow extra in case you have mismeasured. All fuel hoses must be double clamped at each end, so buy hose clamps at the same time, and pick up a few spares. I don’t like reusing old hose clamps, especially on something as critical as a fuel system. Again, buy them at a marine store, and ensure that they’re stainless steel. When you install them, make sure the second hose clamp lands entirely on the barb and not half on the barb and half off. That could pinch or cut the inside of the hose and lead to a fuel leak.
• Prep for Storage. Experts disagree on the best way to prep your fuel tank for winter storage. Some recommend draining the fuel system as much as possible and then adding a fuel stabilizer to what remains in the lines. While this prevents phase separation from occurring to a full tank of gas, its downside is that a great deal of condensation can occur in an empty tank, so you’re still stuck with water in the tank. Other experts, including some oil company experts, recommend filling the tank to about 95 percent capacity, leaving some room for expansion while minimizing the amount of air available for condensation. Both sides in this debate agree that the worst solution is to leave the tank half full.
• Stick It. An engine that knocks, hesitates, or fails to reach its accustomed top speed at wide-open throttle (WOT) may be suffering from phase separation in its fuel. You can test the gas in your tank for separation by applying a special “water-finding” chemical paste to a dipstick and sticking it through the fuel filler or tank access port down to the bottom of the tank. The paste will change color if water is present. Be sure to use a paste specifically formulated for E10 fuel.
• Separate It. Install a fuel/water separator.