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Old 07-09-2013, 08:23 PM
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fmc400 fmc400 is offline
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The linkage on this side of the carburetor opens and closes the secondary throttle plates as a function of the position of the primary throttle plates. In the case of WOT where both the primary and secondary throttle plates are fully open and the throttle is released so that the vehicle decelerates, lever B pushes against lever A to close the secondary throttle plates along with the primary throttle plates. Back at rest, with the secondary throttle plates closed completely and the primary throttle plates partially closed as dictated by the curb idle speed screw, levers A and B don't necessarily have to stay touching. The marks you see on lever A from lever B are from the deceleration action I've described. Nothing you have described sounds wrong.

Note that the secondary throttle plates cannot open unless the choke is open. A lockout mechanism on the throttle side of the carburetor is responsible for this. This appears to be the case of the carburetor in your picture (primary throttle plates open, secondary throttle plates closed, choke closed). I am able to tell the position of the primary and secondary throttle plates based on the positions of levers B and A, respectively.

I'm hesitant to say that I fully understand your original problem and why it's no longer an issue, but as long as the linkage is operating as I described in my previous post, that's all that matters.
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