1985 720 Throttle Valve Switch

[camronnie]

I bought an 85 720 about a month ago with 177k miles, it is a 2wd 5speed, z24, and it been running "ok".  It would have a high idle after warming up, would usually run rich at low throttle but would go completely lean at full throttle, sometimes struggling to accelerate even at part throttle.  Replaced all vacuum hoses and found a few that were bad and a few that were backwards, and that corrected my high idle it seems, but now it wants to die as soon as I touch the throttle because it is going full lean.  Cleaned the carb out and realized the primary was a 94!  Secondary is a 170.  Smallest bit I had on hand was a 1/16", drilled out the primary while I wait on a jet kit, and now it idles fine and drives, obviously runs rich as soon as I touch the throttle, but doesn't die at least.  It also isn't going full lean anymore when I go full throttle.

 

While messing with the carb I found a switch that has an adjustment screw that references the throttle position, I'm assuming this is the throttle valve switch.  Could anyone explain what this switch does and how it should be set?  I don't see anything coming up in the search function here, and about the only info I can find in my Haynes manual is where it goes into the ECU which doesn't tell me anything.  Thank you!

[datzenmike]

A #94 is a California jet. You want 107 to 111. 1/16" is about #158 which will do. #170 secondary is perfect.

 

 

Do you have air conditioner? Is so it's the FIDC or idle up solenoid. Keeps engine from stalling at idle when the compressor kicks in.

[camronnie]

Yes, it does have AC.  So do I set it to just trigger at idle, and switch off at minimal throttle input?

[datzenmike]

 It's only needed when the air conditioning compressor is on and only affects idle by being in the way of it closing. If you are driving above idle it's still on but doesn't matter.