Gen Zen Page 2

Gen Zen - Genset Maintenance
Gen Zen
Part 2: No Strain, Blade Ruiner, A Clean Exchange, and more.
 More of this Feature
• Part 1: Gen Zen
• Part 2: Gen Zen continued

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• Maintenance Editorial Index
• Maintenance Q & A Index
 Elsewhere on the Web
• Northern Lights/Lugger
• Onan

No Strain. Cooling problems are in fact one of the most common causes of genset failure, which is why virtually every manufacturer interviewed for this article considered maintenance of that system a top priority. But Nelson Wilner, president of Mase North America, cites a component not generally considered part of the cooling system as one of the three most common maladies his service people encounter. He says that even a slightly clogged sea strainer can reduce the supply of sea water to the heat exchanger, eventually leading to overheating. Pressman cites potentially more serious maladies. “Sometimes when a strainer is clogged, it can’t do its job and will allow material to reach the raw-water impeller, damaging blades,” he says. “This can cause bits of the rubber impeller to break off and lodge in the heat exchanger, where they clog its small passages.” Kohler recommends checking your genset’s raw-water strainer before every start. Most genset manufacturers urge you to remove at least one side of the acoustical enclosure every few months so that you can take a good look at your unit’s condition.

Blade Ruiner. Many engine mechanics say that when it comes to the raw-water impeller, if it ain’t broke, don’t fix it, and that whatever may be gained by removing an impeller for visual inspection is offset by the possibility that it will be reinstalled improperly. Our experts disagree, urging owners to remove and visually inspect genset impellers at around 400 hours or six months. They cite as a reason degradation that is exacerbated in warm-water environments and point out that even if you don’t use your genset, impeller blades can lose flexibility and take a “set” that compromises their pumping efficiency. The only way to accurately judge the condition the impeller blades are in, they say, is to remove the impeller and feel the blades with your bare hands.

Of course, if you do remove the part, you’d better know how to properly reinstall it.

A Clean Exchange. Pressman is adamant about cooling system maintenance, including flushing the heat exchanger annually. He claims that even if your boat has an effective sea strainer, small amounts of things like sand, marine life, oxidized material, and even sacrificial zincs can lodge in a heat exchanger’s small passages. While you can remove the exchanger and take it to a radiator shop for flushing, Pressman suggests it’s easier and nearly as effective to remove the exchanger’s end caps and clean it with a pressure washer or even a hose. He also suggests scrubbing the passages with a plastic bottlebrush.

Terminal Condition. Another common problem area cited by our experts is the electrical starting circuit. All agree that the prime candidate here is low battery voltage. Most boaters maintain their cranking and house batteries but forget about their genset battery, often because it’s out of sight. Our experts say you should brighten and tighten battery terminals at the beginning of each season and caution that you should anticipate battery life so you won’t be caught powerless. Says Pressman, “The typical battery lasts from three to five years, even with the best of care. After three years you’re on borrowed time.”

Fuelishness. Both gasoline and diesel gensets need clean fuel, but gasoline units tend to be less tolerant of oxidized or contaminated fuel. That’s why our panel suggests adding a fuel stabilizer annually if you expect to not use the unit for more than a month.

Exhaustive Inspection. Both gasoline and diesel exhaust are dangerous and potentially lethal, but diesel exhaust contains less carbon monoxide and has a more recognizable odor, so it represents a slightly lesser hazard. In any case, Kohler recommends a complete inspection of the entire exhaust system every 500 hours or annually, with special attention to clamps and rubber components.

Outta Sight. The popular acoustical enclosure or “hush box” not only muffles sound but also can hide a host of problems. Kurt Hoehne, marketing services manager of Northern Lights/Lugger, says owners should remove one side of the enclosure every three months to allow a brief visual inspection. He urges you to check the integrity of all clamps and fittings and examine the bottom pan for leakage, which will alert you to potential problems. Finally, check the enclosure’s air inlets and exits. A genset needs air for engine combustion and to cool the alternator windings. Too little of either and the unit’s performance and durability will suffer.

And while you’ve got that access panel off, check your V-belts. Wilner cites frayed, scored, glazed, or loose belts as another of his three most common maladies. (The remaining problem is a dirty fuel filter.)

Performing all of these often-overlooked service recommendations should cost you no more than a few more hours a year, but as a reward you’ll have power every time you want it. And that will give you added peace of mind, whether you’re dockside or hanging on the hook.

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This article originally appeared in the May 2003 issue of Power & Motoryacht magazine.

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