Engine: The 25 hrs is as noted too short an interval to tell much. A lot can depend upon the hours the engine sat to get those 25 hrs. Long periods of inactivity can produce high iron in the oil. Light rust can form on the cylinders which then is scraped off when the engine is next started. It might settle down once the initial rust content is gone.
Copper, see comment below. THe other metals such as Moly, tin, lead, chrmium seem to be ok even for the low hours.
Gear: Copper can leach out from coolers where the bronze/brass makeup of the unit can be affected by the oil. Not to be ignored but keep up the testing.
Read the posted article below also.
Lead might be a bit more interesting as it could be solder from the cooler, bearing material or part of the alloy of the cooler body/tube stack itself. Lead is often part of the alloy that makes up the cooler itself. Copper high, lead high.
Generator:
Much the same comments as eng. , not enough hours and long intervals between uses can cause a bit of rust which then gets scraped off elevating the iron.
You don't say this boat is new to you or if you are just starting a testing program. I think I remember you asking about this as a potential new to you boat, CORRECT? So is it now yours?
When you are considering oil changes pick a good oil and stay with it. Base the decision on what is readily available in your area. There may be slight differences in the oil makeup that affects the copper and if you keep changing the copper won't stabilize.
I would also do another test in about another 25 hr interval or when you get home to see if the readings change much or stabilize. I often do this after repairs OR a questionable test reading to see if the questionable readings are still changing or stabilizing.
And my last comment is one shot tests like this are often not of high value unless they indicate something catastrophic such as coolant in the oil which does not appear to be the case.
Testing should be a constant program to get the most out of the information over a period of time to show trends or sudden changes.
JMO such as it is.
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