1983 GSL, 12A, stock Nikki, rats nest simplified.

(Scroll past the images to understand why I'm asking).

What does Choke Diaphragm No. 2 do, and how is it supposed to be set up?

Here are the images of my choke diaphragm #2 as is:



and



By hand, I can move the assembly inward and outward. However, the linkage on the diaphragm is not actuating on the cradle. It can be fully extended to no effect. Googling and searching around netted me Ray's old thread and this image:



If Ray's is right, then I do need to bend my linkage on the cradle in much the same way so that it does actuate. But I don't really understand what it does and if it's related to my high idle issue (See italics below).

History: Tracking down a fast idle issue. All vacuum leaks have been dealt with from a completely redone rats nest to the ACV block off being done (ACV was leaking) to a leak on the carb left by the PO when they reinstalled the Nikki. I've gotten the idle down now after the car warms down but off and on the thing creeps up to 1200 or 1500. I have no idea why so I was lubing the linkages and making sure that they were playing well when I found this. Dunno if it's related, but it's broke so it's getting fixed.

 

As I understand it the no. 2 choke diaphram is meant to reduce the choke valve from full once the engine starts to prevent a too rich condition. Looking at the pictures the linkage looks fine to me.

To test it remove the vacuum line and pull the choke out completely. The choke valve should close completely. Now apply 500 mm-Hg (19.7 in-Hg) vacuum to the choke diaphram. The choke valve should now have a clearance of 1.46 - 1.8 mm (0.0567 - 0.070 in.)

 

That makese sense; I'll try it later and see what if it's working right. Thanks!

 

Yup, it's operational. Thanks for the knowledge :-)