Model NB

    Beginning in 1925 a replacement for the popular model N was introduced, the NB.  The NB was the first to exchange its ignitor for a Wico EK magneto and sparkplug.  No igniters were ever used on the NB, some had a battery and high tension coil but the majority used the Wico.  Available in 1 1/2, 2, 3, 4, 6, 8, 10 and 12 hp they effectively covered all power needs with a good selection on the smaller size engines.  1928 saw the 4 hp being re-rated to 4 1/2 hp.  All engines 4 hp and up used the familiar fly ball governor, 3 hp and under used a sliding weight in the left flywheel.  There were noticeable differences in the smaller engines from the previous Model N's.  The NB had a mixer that bent downward much further than that of the N.  The design of the governor weight and flywheels was also different.  Engines 4 to 12 hp were continued as the NB until the end came in 1933.  Those 1 1/2 to 3 hp fell out in favor of the NC and later ND engines.  

The larger NB engine with fly ball governor.  Also present is the new Wico EK mag.

The differences between the smaller N and NB show up well in this photo.