Parts Illustration above shows only 1 pin. Which is correct for those
models that have the rubber biscuit clutch.
Certain models did not have the clutch. They used a shar pin in the
rear hole in the prop shaft and a short pin in the impeller drive hub
that was held in by a circular spring in the groove around the
impeller drive hub or eccentric cam.
Note that the clutch can be left out and a sheer pin used
on all models IF a short pin and spring are used to drive hub or cam
That requires the spring to retain the pin.
Simple ingenious either or design provided all the right parts are
in place. It is worth noting that prop shaft is same for all modes
from `940 K1 thrue WG4…regardless of brand, single or twin, clutch
or shear pin or whichever water pump.
Louis
Note: the 1940 16 square hole water pump had a more complex way
to drive and retain the water pump oscillator cam. Used same prop shaft. 1941 7 slit design was modified as above. Propeller was
changed to allow for either clutch or shear pin drive..
