Small diesel engines tend to be remarkably reliable. Even in the harsh saltwater environment, marine diesels can last for decades and thousands of hours, largely because they are entirely mechanical (other than the gauges, alternator, and starter motor). If you can crank it started, it will go: There are no computer or electrical components to fail.
The precise timing and supreme efficiency of mechanical diesel engines is a kind of engineering marvel, yet they are wonderfully simple. They need only fuel, air, lubrication, and cooling to run. They are so simple and dependable that many function despite poor (or no) maintenance. However, their high level of reliability can only be sustained if the engine is properly maintained.
Each of the engine’s systems is, of course, crucial to its smooth running. It won’t work well (or at all) if the fuel system has air or particulates in it. Similarly, if the air intake or the exhaust are blocked, you have problems. Overheating and serious damage can occur if the oil system or the cooling system are not functioning correctly.
Most diesel engine manufacturers make it easy for owners to ensure they’re doing the right maintenance at the right time. Most operating manuals have tables for periodic maintenance, spelling out when you should do what. My husband, Seth, and I have, and it’s a measure of the little Yanmar’s simplicity that its maintenance table is only two pages long.
