Re: Nitro 170TF
I don't think Merc has ever changed the control cables at the engine end. Thus, your 3000 should adapt to the replacement engine. In fact, if the replacement engine has the red quick-connect plug at the engine, then every thing should mate. If the older Merc has the side plug, then you may need to do some wiring.
Better answer would be obtained if you post over in the Mercury Forum.