The marine engines have different cams and a number of other parts to allow it to last under the loads a boat puts on an engine.
The ECM will have to retain it's harness and components to allow it to work. Tuning ECM to new installation will take expertise and software allowing changes to be flashed to its memory.
Contact this TT member http://www.mastercraft.com/teamtalk/...=diesel+engine
maybe you could drop in a diesel...