Every other aircraft engine manufacturer out there releases their overhaul manual. What makes Rotax so different? It's not complexity, because a Lycoming TIGO model is just as complex as Rotax, if not more, and they aren't falling out of the sky because of shoddy overhauls. I think it's liability reasons. Even if in the real world no one is going to get themselves killed because they try to follow the manual without proper expertise, Rotax (the lawyers at least, not the engineers) try to claim that they will in order to hold back the information. Ostensibly for our own safety, but common sense and history tell us otherwise.
I understand that Rotax is afraid of tort, but I don't like the claim that everyone but them are too dumb to do the overhaul.
Lawyers and the litigious ruin everything. :(