Steve Chamberlin was experiencing overheating and related problems with his one cylinder Yanmar. Rather than fight the limited engine access below decks to service the engine, he took a more complete approach to the problem:
From Steve: The long term problem with the single cylinder Yanmar is salt build up between the head and block. The head cannot be removed in the boat because of clearance problems. Bill Ingle (Bill’s Marine Service) replaced my engine with a completely rebuilt unit, $4,500, 4 hours.