Last of the last!  The NK was the very last model F&J introduced in 1930.  They were a throttle governed kerosene version of the ND and were built in the same 2, 2 1/2 and 3 1/2hp sizes.  Wico EK ignition was standard as was a geared flyball governor.  The NK did not use a dash pot or water injection like the earlier model K engines.  They did use an auxiliary air valve and featured a small gasoline chamber for starting.  Only a few hundred model NK engines were ever made making them the rarest of the rare in the throttle governed family built by Fuller & Johnson.