It will be a governor.
Generic description based on my Honda engine...
The shaft into the engine will move or turn in relation to the current
engine speed (it's connected to a centrifugal crank driven devce inside).
This should operate the butterfly, but be controlled by the user throttle
control via levers and springs.
Users sets desired speed, governor/linkage/springs/butterfly try to keep
engine speed constant(ish) regardless of load.

You're likely to find that the user throttle control does not directly
operate the butterfly at all, but acts on a lever which is then tied to the
governor assembly etc.

Hope my decription gives you an idea of how it's supposed to work at least!

Alan.


wrote in message
...
I've got to the final stages of re-assembling a Howard 350 rotavator
and can't quite see how the throttle linkage is *supposed* to work.
It has a Kohler 141 petrol engine.

I seem to remember when I took it apart that I thought to myself "I'm
sure it shouldn't be like this" so it's not a matter of having
forgotten how it goes back together, I don't think it was right to
start with. (Considering the state of the rest of the machine this
seems quite likely, talk about bodged!).

Anyway can anyone point me at some picture, description or information
of any sort on how the linkage works?

The 'user' end is just a straightforward cable control.

The difficult to understand bit is not the actual bit that connects to
the butterfly spindle itself. The butterfly spindle has a wire link
to operate it and connects to a 'thing' on a shaft to which the cable
from the control also connects. The 'thing on a shaft' connects the
cable to the butterfly but it also does something by rotating a shaft
which goes inside the engine. It has a spring loaded plate and sundry
other bits. I guess it may either be a mixture controllong device or
a governor of some sort but it's hard to tell.

--
Chris Green )