PS Advisor: 02/06

Diesel Fuel Additives
I own a 1995 Catalina 270 powered by a Perkins Perama M20 diesel. The operating manual says the fuel should have a minimum cetane rating of 45. For the past three years, I’ve had to use fuel with a 42 cetane rating. The only additives I’ve used have been Biobor-JF and Water Zorb. The engine has been run about 40-50 hours a season at slow to moderate RPMs, with no problems. I usually refill the tank when it’s half empty. My three concerns are:

With new regulations for low sulfur diesel fuel becoming a reality and possibly being able to get only 40-cetane fuel, should I use some kind of additive and, if so, what’s recommended?

Are the additives that I currently use okay?

Should I be using some sort of fuel stabilizing additive during the winter lay-up?

Eric Burkert
East Hampton, New York

PS talked with several experts, but got specific advice from Ike White, who is the senior trainer and service manager for Perkins, the world famous English diesel maker that was bought in 1998 by the world famous American company called Caterpillar. White said the cetane rating most often seen these days, at least in Pennsylvania, where he works out of his home, is 37. However, he said it’s not much of a problem to boat owners. Cetane (C26 H34) is an oily hydrocarbon very similar to Octane (C8 H18). Your diesel fuel is not only a fuel, it’s a lubricant responsible for one of the toughest lubricating jobs known to man, that being the lubrication of the diesel fuel pump, which is the heart of any diesel engine—and the clearances therein are such that the pump won’t pass common dust. To be safe, White recommends the additive called Stanadyne (it’s also recommended by General Motors), which adds back the lubricity that went south when new environmental laws called for reduced sulfur content in fuels. It’s not expensive, and there are others on the market. Whatever you choose, a bottle that’ll treat 250 gallons goes for ten or fifteen bucks. As for the other stuff you’re adding, it’s okay but not vital. You’re doing a good thing by refueling often. That minimizes condensation, which is what makes it possible for bacteria to proliferate. Do your engine a favor once or twice a season and run up the RPMs for a couple of minutes and blow out the soot. Back down when the smoke stops. Diesels thrive on hard work; all they ask is clean fuel, good lubrication and reliable cooling. Sailboat owners tend to baby them.

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Tool Corrosion
The tools I keep aboard seem to rust at an alarming rate. Is there a way to preclude this? I’ve tried wiping them down with an oily rag every spring.

Frank Pryzbylynsky
Chicago, Illinois

A really good sealed box might help. But the basic problem is the condensation of moisture inside the boat. Moisture must be present to support the process. Condensation results from temperature differences. If a boat is really well ventilated the interior temperature will change with the exterior temperature, and condensation will be virtually eliminated, thus minimizing the accumulation of moisture and holding at bay the dreaded reddish brittle oxidation. There are lots of good ventilators. Among the best are Nicro’s solar vents, which, by incorporating a solar-powered Nicad battery, provide 24-hour air movement.

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