Comments by "ke6gwf - Ben Blackburn" (@ke6gwf) on "Will Thin Motor Oil Cause Engine Damage? Let's Settle This!" video.

@emotionz3 there's also different emissions regulations in different areas, and oil choice can impact emissions testing, and they probably have to test with the recommended oil.
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@alouisschafer7212 it could be that the manufacturer made a mistake on the first gen engine (EXTREMELY common), either in the engine design, or in the oil spec sheet, and they updated it in the next iteration. You may not be aware of any mechanical changes, but maybe the oil metering passages are now smaller, or maybe they discovered that the original thicker oil recommendation was causing excessive oil pressure under some conditions, or not getting enough oil to certain bearings or something. So assuming that the original recommendations were accurate is risky, because they may have been copied and pasted from another similar engine, and then discovered to be incorrect.
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