Test Flight after annual. Cowl flaps won't stay closed and auto-pilot goes into un-commanded steep turns up to 45 degrees in a few seconds RTB'd. Vacuum line found disconnected after static system filter change during the annual it was re-installed then auto-pilot functioned normally on test flight. Cowl flaps close after Ben re-rigged them but still not as before annual. Point 7 (0.7 hrs) into flight home noticed carbon monoxide puck has turned partially black (I est. ¾ of the area).
