If you look at the OP - he’s asking about small/mid 4 strokes of which there are thousands- my F60 only holds 2.6 quarts. No, he's talking specifically about a Honda BF 50. The oil capacity is 3.3 liters - that seems to me to be fair bit of oil for a water cooled motor that only puts out 50 hp. And certainly not consistent with your unsupported claim that "4 stokes don't hold much oil" (exactly what does that mean, anyway)? And what is the point you are attempting to make?
FC-W is from what many OEM’s assembled (exactly what does that mean?)- and they bench test with F150’s … doubt they‘d want to use automotive derivatives because most outboards are not. All OEM label oils carry this approval … Mystik and others do as well … I sincerely doubt that you know what Yamaha uses to bench test their 150s(or any other motors for that matter) and even if you miraculously did why do they continue to recommend non FC-W oils in their manuals if they're not appropriate?
Let's get really specific and to the point here with a fact for the OP as opposed to unsupported anecdotes. Copied directly from the Honda BF50 owner's manual:
Engine Oil Recommendations
Oil is a major factor affecting performance and service life. Use 4-stroke detergent oil.
SERVICING YOUR OUTBOARD MOTOR Spark Plug Service
SAE 5W-30 is recommended for general use.
Honda recommends that you use API service category SG, SH or SJ oil. The SAE oil viscosity and service category are in the API label on the oil container.
I shared what a large/mature service department did on their own - tested a long run offshore at WOT … Visible air in oil might be OK for some - not others. Back to your first reply - who drives cars like that … ? Or has very humid air intake … This is nothing but an unsubstantiated anecdote and a poor one, at that, although it is humorous. It is in all respects the equivalent of my local Dodge mechanic telling me that synthetic oil will ruin my Cummins because it is "too slippery" Again, I guess these "guys" (and you) must know better than the major manufacturers with respect to appropriate oil specs and clearly, according to you, their recommendation for automotive grade oils is inappropriate. For readers who find these n=1 anecdotes more compelling (or compelling at all) than the mfg specs, well, I guess they're you're audience and are, of course, free to do what they want.
What you posted is that they “recommend” NMMA’s oils - doubt they can force you to do anything … but it’s similar to other warranty debates folks have here over how they interpreted the manual (mmm, I never commented on warranties. Perhaps you're referring to another poster … I'm not sure what this has to do with this discussion - read the manufacturers' recommendations that I posted. No interpretation required, it's right there in black and white for everyone to read. Those are the facts of manufacturer's recommendations. Read the three excerpts from the Suzuki, Yamaha and Honda owner's manuals that I posted. I'm not sure why it's controversial for guys like you to run specs (any or all) recommended by manufacturers. I know, I know... you and the guys in your local service shop know better. The automotive world is moving away from the viscosity spreads that outboard OEM’s continue to recommend (and test) in some motors - another reason a higher TBN HDEO is perhaps a better/proven alternative to save money on oil …Not sure why we've now introduced a TBN discussion, but it's a red herring. A HDEO that meets the specs is no better than any other oil that meets the manufacturers specs. If you have proof that it is, by all means share it with us. Automotive oils that meet recommended viscosity recommendations are, and always have been, readily available.
(but Noack should be compared) …