no idle up with air-con on

[trustpower]

after rebuilding my pro city motor (er1 atmo) i bolted on a fresher looking carby from a wrecked city i have, which was not fitted with aircon.

My city has air con, and im wondering if theres a problem with the carby ive just put on not being setup for an air-con'd city.

Every time i switch the air-con to max and i hear the compressor click, the rpms drop from around 800 (normal idle) to about 400-500rpm.

Could the throttle nudger to idle up when the aircon gets switched be incorrectly set being that the carby never had to idle up for aircon in its past life?

also, I've checked my connections briefly and everything looks okay and plugged in etc. Ill have a closer look later today. Any suggestions?

[James]

Ill have to check the manual but i believe the AC idle up thing it a little solenoid isnt it? Like about the size of a C- battery that switches vacuum onto one of that vacuum cans that pulls the throttle opena little bit?

Should be pretty stright forward if this is the method it uses.

[trustpower]

From what i can gather yeah, theres a little solenoid on the firewall that has a wire running into it and a vacuum line as well. The vacuum line runs to a little throttle nudger. The problem i've now got is working out how to use the throttle nudger screw to set the idle with a/c on as well as the idle speed screw to set the right idle without a/c on.

Ive had a play with it yeterday and last night. I got it sort of working okay, but then it didnt sound right, and when the engine was colder my idle with a/c off was unusually high at about 1400rpm, but as the temp came up it dropped back down to about 800rpm.

The manual from what i can gather, just points out the adjustment screws, not any specs or anything.

Might just need a bit of trial and error.