lines 21 represent the connection between the motor and the combine a computer 22 and a filter 23 connect to the motor and the housing the computer can be a computer used in the engine or it can be a separate unit the computer is used to synchronize the operation of the combine with the engine to deliver fuel at the precise time the filter is used to clean the air that passes through the housing which cools the motor and removes dirt and debris from the housing it also keeps gas away from the motor fig4 is a top view of the motor gear and air tube housing the housing 17 is a rectangular box that holds the motor and an air tube 24 and an air tube 24 a the figure also shows the motor shaft 25 onto which the gear 12 is installed fig5 is a front view of the motor gear and air tube housing here the inlet air tube 24 a and motor are shown in proper special relationship note that the housing 17 has a pair of bosses 26 that are used to hold screws 27 that hold the lid of the housing in place fig5 a is a front view of the motor gear and air tube housing used in a top arrangement with a combine in this view the air tube is shown on the other side of the housing to prevent the air from mixing with the gas fig6 is a rear view of the motor gear and air tube housing note in this view the motor is not shown it has only one shaft that exits.