I'm looking at a boat that has a Detroit 671 engine. The listing states that this engine is rated at 135 hp. I've seen many listings for boats with 671s rated at from 135 to over 700 hp.
I'm new to diesels in general and Detroit diesels in particular. Can someone explain what governs the horsepower rating of these engines and how they can be rated over such a large range? Is there a book or web site somewhere that can help me learn more about them before I commit to buying the boat? I'm also looking for a source opf performance specs for this engine - including a fuel consumption curve.
Thanks in advance for your help.