Quote from: Breakin Away on November 15, 2016, 07:16:35 AM
I had checked the manual. The latest edition of Westerbeke's Operator Manual, which covers all B series models, recommends 15W40 for everything. No mention is made of single grade.
Agreed. I've been using Rotella T 15W-40 from day 1 and hope to do so, so long as I can still find it.