It is possible to marinize this engine but I don't know where you would get all the parts required.
Years ago we used to supply parts to people to marinize their own engines however, as the Beta Marine name is on our parts, we got the blame when a less than perfect job was done as people do take short cuts and leave out some parts to save costs. As a result of these instances we decided not to supply heat exchangers or flywheel housings to people who want to build one generator or one engine.