Abstract: A shutter valve construction for the exhaust system of a marine engine that discharges exhaust underwater. The valve construction includes an adaptor having an annular body that is adapted to be engaged in the end of an exhaust pipe. Opposite sides of the body are provided with outwardly projecting bosses which are received within holes in the exhaust pipe to position the adaptor relative to the pipe. The valve construction also includes a butterfly-type shutter valve that consists of a pair of valve members which are hinged to a hinge pin that is removably connected to the adaptor. To connect the valve to the adaptor, the ends of the hinge pin extend into opposed openings in the body of the adaptor and receive resilient grommets.

Abstract: A system for a trimable marine stem drive shifts the trimable range on a conventional hydraulic trim system. The system includes an enlarged cylinder anchor pin hole in the drive shaft housing, an anchor pin smaller in size than the enlarged anchor pin hole located in the drive shaft housing, and a movable trim adjustment insert that is inserted into the enlarged anchor pin hole to secure the anchor pin in a fixed position within the enlarged hole. It is preferred that the enlarged anchor pin hole be a substantially horizontal elongated hole, and that the trim adjustment insert be placed rearward of the anchor pin to position the anchor pin in a forward position, or forward of the anchor pin to locate the anchor pin in a rearward position. The invention shifts the trimable range of the drive, while maintaining vibration isolation characteristics available in conventional hydraulic trim systems.