I have been a boatdiesel subscriber for almost ten years. This is what I have found:
Some engines are well represented by pros and others not so well. The good in order of support:
1. Cummins- Tony, Ski and Paul are the absolute pros on this engine.
2. Cat- Dave is the pro on this one
3. Volvo- Dick for this one
4. Yanmar- Pretty well supported by Tony and others and might be a 2 or 3 if there was a single goto pro.
5. Gensets- Ski is the pro for all diesel gensets.
The others get some support but not as well. The larger Lehman and Perkins ok. Westerbeke, Beta, and smaller Yanmars not so good. Clark, Ski and others try, but this is basically a power boat engine support forum. Also I suspect that sailboat engines have far fewer problems than high performance turbocharged engine do.
I have never, ever seen someone trying to sell something on the boatdiesel support forums. Peter wouldn't allow it.
Tony is available for personal telephone consultation for a fee. But he gives freely of his time on the forum and has helped hundreds solve their problems on the forum.
You can post, create a thread, post some more and receive advice for free without joining. You can't post or see pictures or access the pdf library unless you join. That seems fair to me.
There is no better general resource for marine recreational and small commercial diesels. If you are even slightly hands on, join and pay your $25. It will help keep your engine running right.
David