boat poker, its a good article.
Cards on the table, I have more than 50 years in marine engineering and in that time have had many thousands of oil analysis reports across my desk.
Oil analysis definitely has a place in the industry, can be a useful tool, can provide forensic data and has applications within condition assessments and maintenace regimes.
History lesson, jump this paragraph if you are in a hurry! The process was originally created for large systems, you simply can not throw away large quantities of expensive material based on xx hours in operation, rather you sample it and determine the oil's suitablity for further use and what treatment may be required to ensure that suitability continues. Originally it covered only the basic properties, viscosity, TBN etc, still its most important use in my view. This was expanded to include wear materials (by spectographic examination) when the equipment became readily available, reasonably sized and at reasonable costs and as a kind of added service offered by the oil suppliers to differentiate themselves, thus it was essentially a marketing move for a process that was technically available at low cost. For such a process to deliver reliable results the laboratory must perform to the required quality standard AND the sample must be drawn in a controlled and repeatable manner. In such a situation the results can be trended and over time can become useful. Later, people realised it was a product / service they could sell and now it is generally available.
In engines and other systems of the size that are addressed by this forum, I believe that frequent oil changes provide absolutely the most cost effective maintenance possible, sampling provides very little for the money in real terms, the money is better spent on the oil
I dont think any of these "small" engines are adequately equipped to draw a sample in the controlled manner required (as standard) and whilst taking an oil sample from the sump or wherever may provide some added interest (and certainly in itself it does no harm) I dont actually think it does much good, it's akin to the car enthusiast polishing his car every week, it doesnt hurt it but neither does it improve any measurable parameter of the vehicle.
Value of the analysis, just like you would not expect an MD to give you a (medical) diagnosis based solely on your pulse rate, anyone who is giving a diagnosis based solely on an oil analysis is kidding you. Together with other information spectographic analysis can help with a diagnosis, but it is unlikely and it is certainly beyond the scope of "normal" mechanics. As part of a test and trial process a lead mechanic should be able to draw some conclusion which an oil analysis may reinforce but he would have probably got there anyway with the other tools at his disposal
Of the thousands of reports I have dealt with I can't remember one which saved us from a failure, although I can remember a few instances where this may have been the case had the results been returned and reviewed quickly enough. In these few cases they merely helped us in a forensic sense to understand the origin of the failure, sometimes this is not as simple as it may sound when all you have is a large pile of scrap !!
So, as always, its your boat, your money and your hobby and if taking samples adds interest it certainly does no harm in itself. The harm comes from the "quack" diagnostician who leads you to waste more money.
