Quote:
Originally Posted by kerry
I'd look into the role that the butterfly valve is playing. Is it possible to keep the butterfly valve open while idling not allowing the buildup of vacuum in the intake manifold and see if you get the same smoke when pulling away?
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Thanks for the idea, unfortunately the short response is no that won't work, for the longer version I will quote forum member Govert who is far more knowledgeable on the 616.916 IP function than I am:
Quote:
Originally Posted by Govert
The vacuum for the governor of the pump is not created by a vacuum behind the butterfly valve, but by a venturi under the butterfly valve. The valve controls the amount of air flowing through the venturi. Also an increase in the speed of the engine will increase the air flow through the venturi.
The vacuum works upon the membrane. The membrane connects to the rack, so more vacuum and the rack moves towards the stop position. There is also a spring inside the governor that pushes on the membrane and so, if there is no vacuum, the membrane moves the rack to the full load position.
The rod to the IP controls the auxiliary mechanical governor, i.e. the poppet cam. That steadies the rpm at idle and at low speeds, otherwise the engine would be "sawing".
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