Re: Yanmar hard starting question
No surprise thatt Mr. Berlin is clearly stating their recommendation is based on liability rather than engineering.
"Rotella is designed for diesels, is used by several manufacturers as the OEM engine oil, but it is not CF-4 because CF-4 was declared obsolete in 2007."
Ah, Mark, most engine makers would say "must use oil that meets or exceeds API standard CF-4..." If they were amateurs who said the engine simply required CF-4, well, that's what open mike night at the comedy club is for.
Engine makers have gotten used to lubricant standards being a moving mark for a long time now. This ain't the 1950's any more.