Marine drive system with improved drive belt

Abstract

An outdrive system for water craft includes in an embodiment use of plastic or other relatively flexible material, e.g., compared to metal, as a housing material, and techniques which enable and/or at least facilitate use of such housing material. Several of those techniques employ a flexible member, such as a belt, to couple power between the input and output of an outdrive, and heat conducting back bending surfaces to urge the belt legs toward each other and to remove heat from the outdrive, an anti-shear stuffer or fence to reduce energy losses such as heat, and lubricant requirements, and/or an eccentric mechanical tensioning device for the belt. The invention also relates to use in a vehicle drive, especially for water craft, of housing materials a substantial part of which are not subject to corrosion, galvanic action and the like. Other features include a rotational shock absorber system, an output shaft support, an improved sprocket tooth profile, a water by-pass silencer, an L C (analogous to an electrical inductor and capacitor filter) exhaust silencer, a split eccentric tensioner, an active tensioner, a transmission and a transmission shift mechanism, tensioning protocol and a cooling method. Also, in an embodiment the housing may be made partly or entirely of thermally conductive material, such as, aluminum, which facilitates and enhances heat removal by conduction to the water in which the outdrive is immersed.