is also provided with the usual carburetor 64 having an air intake through an air cleaner 65 the engine is also provided with the usual spark plugs and ignition cables 66 and 67 leading to the spark plugs the engine is provided with a conventional exhaust manifold having an exhaust pipe 72 connected to the manifold the engine is provided with a vertical output shaft 83 on which is secured the impeller as will be presently described referring to the exhaust gas housing 43 this housing rests upon and is secured to the bottom wall 32 of the shell 30 this is a gas tight housing and is secured to the floor 32 by any suitable fastening means the belly pan 47 rests upon and is secured to the exhaust gas housing 43 the housing 43 thus supports the engine the exhaust gas chamber 43 is secured in a gas tight manner to the impeller housing 44 secured to the rear of the belly pan 47 is a one way valve 45 which permits any water in the belly pan to drain out of it but which prevents the entrance of water into the belly pan referring to the impeller housing 44 this is best shown in fig3 it should be noted that it has a central portion 75 in which is located the impeller 76 the impeller 76 is mounted on the cover end of the vertical output shaft 83 of the engine because the vertical shaft of the engine is very short and because the engine and the impeller housing are both securely fastened to exhaust gas housing 43 there is a minimum of vibration the impeller.