power head and carries a lower unit 16 in which a propeller 17 is rotatably supported and journaled the engine 12 drives the propeller 17 in a known manner the engine 12 is provided with an induction system including a silencing device 18 which may be of any known type including one with one or more expansion and or resonance chambers an air inlet 19 in the inlet device 18 opens into the volume 14 and draws induction system air from this volume this air is fed to a charge forming device such as a carburetor 21 the volume 14 communicates with the atmosphere through an appropriate air inlet opening which may comprise a rearwardly opening air inlet 22 the engine 12 is also provided with an exhaust system that includes an exhaust pipe baffle plate 23 for covering a portion of the exhaust system although the inlet device 18 is intended to provide some intake air silencing there will be nevertheless sounds which emanate from it and which can pass to the atmosphere through the opening 22 as shown by the arrows in this figure in order to reduce such sound transmission and to provide further silencing a baffle plate 24 is contained within the volume 14 for breaking up this volume and also for reflecting the sound waves back from the inlet device 18 toward the front of the cowling as shown by the arrows in fig2 in effect the baffle plate 24 also provides.