Hi Peter and welcome to the Forum. I know of the engines obviously but nothing about them as far as maintenance. Keep asking the questions and be patient for replies as members do not always log in to check it out.
Have a look online at Plough Book Sales in Vic I think as they have many hand books. In the mean time is there any particular piece of info you need that might spark things up as a general question no one can tell what it is you need.
You can also try sending a PM to a member called Anzani ( from memory) look him up in the members section, he has a huge collection of marine engines both popular and very rare.
A final choice is to join yet another Forum named Smokstak Downunder as they also have a Marine section too.
Sorry TOM if the last comment offends, it is not intended to do so.