For the first stage of reconditioning, Dallow arranged the MTC's hoses to draw fuel from the lowest point of one of the boat's two tanks, pump it through the coalescer to remove water and solid contaminants, through the Algae-X conditioner to break up sludge, and then back into the tanks via the on-deck fuel fill. Accessing the low point of the tank meant removing the fuel-gauge sending unit, a simple job in this case, since the sending units for both tanks were easy to reach. Some folks won't be so lucky and will have to find other ways to get the intake hose to the bottom of their tanks. But drawing fuel from the tank's lowest point is important to pull out as much of the solid gunk as possible, so pulling it out of the fuel pickup isn't a good idea.
At 900 gph, it didn't take long to circulate the 75 gallons in the first tank. Dallow let the unit run long enough to condition all the fuel several times, then shut down and drained the coalescer. There was some sludge in the bottom of the sample, but not as much as I'd expected. Dallow then reconfigured the MTC-1000's valves to add the 3-micron-fine filter to the circuit to add a final polish. Again he circulated the fuel a few times, then drained some more. Now the fuel was clean and clear. He switched the hoses to the other tank and repeated the process. The whole procedure took a couple of hours, during which Dallow spilled not a drop of fuel.
Once the fuel is polished and reconditioned and an in-line fuel conditioner has been installed, O'Connell recommends adding an appropriate amount of Algae-X AFC-705 Fuel Catalyst. (An eight-ounce bottle will treat 320 gallons of fuel.) Using these chemicals after mechanically treating the fuel takes care of any sludge that remains in the tank, he says, while preventing future sludge formation, improving combustion, and reducing emissions. "Using your boat a lot minimizes the problem [of sludge], but not all the fuel is ever burned; some is always left, but adding new fuel to old doesn't make the old fuel new again," O'Connell explains. He adds that mixing fuels from different refineries can also cause problems since each company has its own cocktail of additives, which can react badly with one another. Chemical treatment prevents this, too; it's inexpensive insurance. (Algae-X 705 Catalyst also preserves ethanol-blended E10 gasoline.)
With Ava T. powered by clean, reconditioned, and chemically treated diesel fuel, Thiel reports that he enjoyed a trouble-free 2006 boating season. Not only that, he says he caught all his flights with plenty of time to spare.
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This article originally appeared in the January 2007 issue of Power & Motoryacht magazine.