I would suggest that if one has to ask the OP's questions, the answer is that one has neither the sailing skills or the mechanical skills to undertake the project
, unless one has lots of time and really wants to enjoy a potentially long and expensive learning
There are plenty of older threads about the costs of replacing or reviving a dead engine
. And why boats that were only offered with inboard engines, shouldn't have outboards bolted on.
Usually it hurts less to come up the learning
curve before getting married to a gaping hole in the water
. (An old boat with issues.)