LSD? means Low Sulpher Diesel which now has a low sulpher content of just 50 ppm, which is short for parts per million. The old stuff has a whopping 500 ppm by the way.
LSD? should I change to it?
Justin dug around and found this for starters.
Roy – there alerts for leaking seals, fuel pump problems, and slightly reduced lubricity for LSD with older engines. Yanmar recommends an additive for some of this. While its not a big issue – its not a pure win going to LSD on marine engines yet. I believe from 2014 new marine diesels will be designed for LSD
More on this just now.
Taken from this link http://dec.alaska.gov/air/anpms/ulsd/ulsd-q&a.htm
For myself, I will continue with the old diesel fuel, its best for the engine and its also a lower cost!