Engine oil analysis - Worth it or No?

[MapisM]

For those of you who think it's not necessary to take oil samples when investing in something like a £250 k 10 year old boat ask yourself what would another £60 matter on the survey costs

Well, from a mathematical standpoint, 60 quids on my zero survey costs would have been infinitely higher...

Jokes aside, I never meant that oil analysis is completely useless.
Just, as I said, "a bit overrated" - particularly when not coupled with some history, which is VERY rarely the case, upon purchase of a used boat.
And after all, what would prevent the seller of a boat with a knackered engine to have the oil changed right before the sea trial...?

But that aside, my previous questions still stand:
1) was the "bad" engine running perfectly, without smoke, oil emulsion, or any other symptoms that an experienced engineer like yourself would have noticed without the oil analysis? Mind, I'm not saying it's impossible, but I do think it's rather unlikely.
2) if asked by the current owner, what would have been your advise on the best course of action?
Not later than 10 mins ago I read a test certificate which was sent me by a fellow forumite which I'm not mentioning unless he wants to (thanks anyway mate, interesting reading), where the recommendation upon a rather bad test result was "Purge, flush and replace oil immediately"...

 

[Greg2]

We nearly bought a boat with a questionable service history and oil that hadn't been changed for several years. My instinct was to get oil samples, which was supported by Volvopaul. Interestingly another surveyor who I know and a couple of local (to me) marine engineers said it was a waste of time and that a single sample in isolation would be unlikely to provide any reliable results i.e. even if they showed high levels of of the wrong things this wouldn't necessarily be a reliable indicator that something was wrong. The surveyor had an engineering background and as suggested by MapisM, his view was that he would know if there were potential problems from an inspection.

Bottom line is that I thought they would be an additional source of information to consider so we went to the boat to run the engines up and get samples but they smoked a lot. Didn't clear at all with time or higher revs so we withdrew from the transaction - didn't take samples and kept the kits for another day. Really don't know if there was a problem with the boat, maybe there wasn't, but we just couldn't live with engines that smoked as much as they did.

 

[QBhoy]

Worth testing if the boats history is unknown, certainly. One might question it's worth after this and regular as manual service intervals and oil changes ?
That said, if it's recommended in the manual....by all means. Good thing to be aware of.....if it doesn't panic you and take the fun out of boating, haha.
Finning are a good start, but there are many in the uk who can do this....Intertek, perhaps the most respected and who I use on a larger commercial scale.....
As with all oil sampling and testing, if it's not just a one of pre purchase and Should you seriously be going down this route, it's best to obtain a baseline for acceptable reading and build a history from there.