Abstract: In an engine assembly including an engine block carried by flexible mounting members on an assembly frame, the engine accessory such as the alternator and compressor are carried on the frame rather than on the engine block itself. The accessories are belt driven from a main drive pulley of the engine. In order to accommodate rotational movement of the engine on the flexible mountings, the accessories are pivotally mounted on the frame and are connected to the engine block by a tensioning assembly which lies generally parallel to a line joining the rotational axes of the drive pulley of the engine and the driven pulley of the accessory. The pivot mounting of the accessory is located underneath the accessory to one side of the line joining the axes and such that the weight of the accessory is communicated through the pivot mounting to the frame rather than to the engine.