More info will be better, what size, horsepower, same engine
for same engine?
If the footprint is the same and you dont have any major project
in the engine room, like repair roten engine stringers, or replace prop or shaft etc...is only the price
of the engine plus the labour to lift
up the old engine and drop the new one and screw it to the engine bed
, conect fuel
, trasmision coupling , panel, electrical
stuff and a dozen of small things , here in St marteen we can get a 4JH for something around 12000$ , labour i dont know , it depend of many factors.