Hello Nico,
Congratulations with your new engine. I couldn't see the way you've organized your exhaust system. It's something that has worried me when I changed my old Volvo with a new Beta Marine BD722/20Hp engine. The point is that the level of the exhausts of new engines are generally situated much lower (often under the waterline level) then the good old Volvo's, which means one has to think how to avoid to get water back into your engine, specially when the boat is healing of the engine is running in choppy conditions. Did you install a water lock, for instance?
Beste regards,
Frans van der Wel
B978 - Aemilia III