How to communicate with an OPD Partner?

Having spent 14+yrs working exclusively with start-ups and being a part of product development life cycles for over 30 startup products, I have observed reluctance from founders to outsource the core engineering part of their product. When I tried to dig out the reasons behind their reluctance most feedbacks pointed towards communication overhead, pace of the development and deviation from the expected outcome. But when I analysed further, I realised that those were only the consequences of the communication gap which in turn is a primary concern.