A lot goes on inside a boat engine, and akin to drawing blood, and an engine oil sample analysis (OSA) can tell you a lot about the health of your boat’s motor. While a single sample may not give you the whole story, an OSA creates a “baseline” that helps you look at your engine’s health over time. That’s why some mechanics and surveyors recommend taking one sample every year. But what does a typical oil sample analysis include and what does it tell a boat owner or buyer? BoatUS, the nation’s largest boating advocacy, services and safety group has some answers.
Most oil sample analyses will include the following:
Spectral Exam: A spectrometer is used to find the quantity of various metals and additives in the sample – useful for finding excessive wear in bearings, pistons, rings, cylinders, valve train and gears. It also determines the composition of any oil additives.
Viscosity Test: The thickness of the oil at a specific temperature is tested – useful for finding fuel dilution, the breakdown of viscosity enhancers or other contamination.
Flash Point: Tests the temperature at which vapor from the oil ignites – contamination can cause a specific grade oil to flash higher or lower than the design flash point.
Insoluables Test: Insoluables are typically abrasive solids – higher readings are usually byproducts of incomplete combustion.
An OSA typically costs about $25 by mail or at a local repair shop.
If you’d like to learn how to take an oil sample or need more information, see the story “Oil Sample Analysis” by Alison Mazon at BoatUS.com/oilsampleanalysis.