Well I just bought one, and like you I am trying to gather as much info as I can. We run these deutz air cooled engines in our trenchers at work and they are tough and never run hot so that's why I bought the tractor. I have learned a few things about it in the couple weeks I've owned it, the best thing I found was an online manual for it, but it's in German. However using Google translate I was able to gather a good bit of info, but it would not translate all of it. The trouble I'm having is the wiring is all chewed up by rats and I'm trying to figure out how the sensors were wired, although I think I got it pretty close. What the story with your D4506?