Abstract: A balance shaft arrangement is for a marine engine having a crankshaft supported for rotation about a crankshaft axis and a drive gear supported for rotation with the crankshaft. The balancing arrangement has at least one balance shaft, and a driven gear being driven into rotation by the drive gear, the driven gear being connected to the balance shaft so as to drive the balance shaft into rotation. The driven gear is selectively radially positionable towards and away from the drive gear. A dampening member is disposed between the driven gear and the balance shaft, the dampening member accommodating radial positioning of the driven gear with respect to the balance shaft.

Abstract: Installation and assembly of an outboard motor made in accordance with the present invention is significantly simplified. Since no spline connection between the sleeve and the crankshaft is required, the engine can be attached to the adapter plate in a much more simplified procedure as long as the pairs of pins are placed in non interfering positions. Because the sleeve of the present invention is driven directly by the crankshaft, without involvement of the driveshaft, the present invention allows the driveshaft to be installed into and through the adapter plate more easily than systems known in the prior art.