Tony's Tips

Lead Line — January 2002
By Richard Thiel

Tony’s Tips
Sound like anyone you know?
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I was looking for grist for this, our annual engines issue, when I happened upon a gem of a Web site for the roughly 50,000 of you who own diesel-powered boats. is the creation of Peter Compton, a former aerospace engineer who created it to promote his book Troubleshooting Marine Diesels. I suspect Compton to be a sailor, but no matter. His site is a winner, offering technical articles, classified ads, forums on particular engines and repower projects, and a small selection of parts for sale. It even covers marine transmissions and gensets. is free, although an annual membership fee of $25 gets you discounts at the site’s bookstore and access to a number of features, including a reference section called Members Toolbox and a cool program that determines "the correct diameter and pitch of a propeller for any given vessel and engine."

Whether or not you pony up the fee, you get access to a lot of good stuff, including columns by a guy named Tony Athens, who also runs an engine business called Seaboard Marine in Oxnard, California. The month I logged onto Athens’ column, "Tony’s Tips," which was entitled Engine Life, a somewhat flat-sounding headline for what turned out to be a very pithy column. The premise is that a lot of engine failures chalked up to unexplained phenomena (aliens? gremlins?) can in fact be traced to one of six causes.

Overpropping. Listening to some builders and dealers, you’d think propping was black magic, but Athens lays out the basics. The one that rang a bell for me was what he calls "swing loads," variable loads of things like fuel, water, gear, etc. that can change the displacement of a boat by 6,000 pounds. Athens points out that when a boat carries this kind of weight in the real world, the result is often black smoke, low maximum rpm, and even engine failure. I was particularly impressed that he recommends the installation of turbo boost gauges as the only real way to accurately measure load.

Lousy operating environment. Athens says this is even more prevalent a cause of engine failure than poor maintenance, a conclusion I’m not sure I buy, but his observations are valid nonetheless. His main gripe is with saltwater ingestion, and he points out that he has seen many owners scrupulous about oil and filter changes who ignore the signs of saltwater damage. He says, "a clean, dry engine room with good ventilation is one of the most important parts of engine longevity."

The nut behind the wheel scenario. He upbraids owners who don’t do maintenance, don’t pay attention, and "operate on the edge." Sound like anyone you know?

Installation-related failures. Just so you don’t think he’s beating up only on your fellow boat owners, Athens trashes builders who create designs that allow the intrusion of salt water into the engine, create excessive backpressure, and eventually cause leakage.

Just poor maintenance. Surprise! He isn’t talking about ignoring oil changes, valve adjustments, etc. He’s talking about owners whose failure to catch a simple problem leads to a catastrophic situation, like an overlooked worn idler pulley that fails and takes with it major coolant system components. He also claims that today’s lighter diesels "just don’t have the extra beef" of older engines and so are more prone to such failures.

Fuel system failures. Because today’s diesels have much higher fuel rates than older engines, Athens says, filtration capacity is far more crucial, so owners need to be especially watchful of contamination.

You might not agree with how Athens ranks these causes, but if you’re an experienced boat owner, you have to admit a lot of what he says rings true. This might be a good time to see if Tony’s Tips can help you take better care of your diesels.


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

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