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What a Walker FuelSep can do for Your Boat

The FuelSep, from Walker Engineering

Give Yourself a Break

Add a FuelSep to your engine’s fuel line and get ready for a cleaner burn.

If you have cruising in your plans for the coming year—real cruising where remote island outposts may be the only refueling option—a Walker FuelSep may be a sensible addition to your fuel-line defenses.

That was the thinking on Arawak, the 1996 Grand Banks 42 Motor Yacht project boat that is the centerpiece of the My BoatWorks project, which is all about preparing a real boat for real cruising. The Arawak team and Mastry Engine Center ( repowered  Arawak in St. Thomas with a pair of new Yanmars and further extensive mechanical and electronic work was performed at American Custom Yachts in Stuart, Florida. ( Her hull was then painted at Yacht Service Ltd. in Amityville, New York (, and she has begun to tour the boat shows.

The FuelSep, from Walker Engineering (, mounts in the fuel line between the fuel-water separator and the engine fuel filter and reduces exhaust soot while improving fuel economy and lowering exhaust temperatures and engine noise levels. The best part about FuelSep? Install it and forget it—it’s got a life expectancy of 5,000 hours or five years. Of course, it’s key to follow the installation instructions, which stipulate a vertical installation with the inlet at the bottom and the outflow at the top.

How does it work? “In layman’s terms it breaks up the longer hydrocarbon chains into more medium chains that burn more completely,” says Mike Delillo, vice president of sales and marketing for Walker Engineering. “You’re not adding anything, but the structure of the fuel behaves like it has a higher cetane rating and is more friendly to oxidation and burning. That’s why you get the better burn because there’s nothing left of the unburned, longer chain that would pass through the exhaust and stick to your transom or cockpit.”      

The FuelSep uses no magnets and will not solve all fuel problems, such as those coming from algae growth and tank sludge. Units start at $400 for diesel engines. They’re also available for outboards. One FuelSep is needed for each engine, and they can also be used on gensets, to reap the aforementioned efficiency benefits and reduce boatside fuel slicks some boaters see. Like the catalytic converter on your car, the FuelSep contains pellets that expose fuel to a proprietary combination of metals. And it’s recyclable—simply send the old unit back for replacement.

The proof is in the cruising. Delillo told me about a call from a client who had installed the system on his boat with a pair of Detroit Diesel 8-71s. The boater called to complain after seeing no change in soot or engine performance. “I told him typically we like to see a 35- to 50-hour break-in period,” Delillo says. “So the good fuel runs through the system and starts to break down the carbon in the engine combustion areas.”

Turns out the boater had not completed the break-in, but he called because he was leaving soon to cruise from California south into Mexico for five weeks. Delillo told him: “Have a nice vacation, and of course fuel the boat up. Plan on calling me in a couple months, and tell me if you see an improvement.”

“Sure enough, he called back,” Delillo says. “He says, ‘I got to tell you this—first thing I need to apologize.’ Then he went on to tell me he’d headed out and gone to Ensenada and beyond, and he said, ‘My transom was filthy and I kept hearing your voice as I scrubbed it down. At one point I even filled up with bad fuel.’ Anyway he continued down to Cabo and stayed there. And then he said, ‘But on the way back my transom was spotless, and that was with Mexican fuel.’”

Have a look at your engine efficiency and how clean your exhaust appears. A FuelSep may help, and could save some scrub-brush time after a day on the water. And that’s something to call home about.

This article originally appeared in the January 2016 issue of Power & Motoryacht magazine.