Model K Mixer

     The 3-12hp model K engines used a mixer somewhat like that of the earlier N Kerosene but of a new design.  It still contained a gasoline reservoir for starting purposes and still had dual needle valves but they were now arranged differently.  The reservoir's suction pipe contained its own check valve which is accessed by a pipe plug.  An auxiliary air valve was now included as well.  This valve utilized a light spring to hold it closed.  It's purpose was to admit additional air during heavy loads to prevent the fuel mixture from becoming too rich.  It will have 3 small holes drilled around the center stem and these should be kept clear.  The valve itself should be lubed with a light oil and kept working freely at all times.  All sizes of early engines initially had the water injection feed located in the mixer body itself.  This was quickly changed to feed into the throttle elbow itself on the 3 and 5hp engines.  The larger sizes retained the same feed location but the casting now incorporated a tee with plug to drain the system in cold weather.  An elliptical cast brass butterfly valve was set into the throttle elbow and secured to the bell crank with a taper pin.  Most engines had a notch milled into the valve to achieve a minimum amount of air flow.  Starting in 1918 a setscrew was installed into the elbow, it lined up with this notch when the butterfly valve was in its closed position.  The screw apparently was used to close up the notch if required.  The mixer also served as an overflow chamber if the engine was fitted with a fuel pump and outdoor main fuel tank.  A series of welch plugs were located around the mixer body.  They were initially there due to the core work required on the casting but also served a dual purpose.  Fuel was pumped into one of the welch plugs located in the casting's side.  A standpipe was located in place of the bottom welch plug, it serving as an overflow to keep the fuel level constant.  The "gasoline" throttle once used for staring only was now the main fuel supply throttle valve.  Now what was the main fuel tank in the base became the starting tank and the "kerosene" throttle was used for starting.