I have an 85 with a 12a. I used a procedure I found on here to adjust the idle. From all the symptoms it sounded like it had a vacuum leak. The car still runs fine when cold or when the choke is out but now it will not idle at all. No matter where I put the idle speed screw it has no effect. The tach just slowly descends to zero and it dies. If I pull the choke out when it is warm it runs. But why does adjusting the idle speed screw have no effect?

 

it sounds like you have a vacuum leak. PM, vipernicus42 and tell him johncaleb sent you. He just helped me out and now it idle's runs great . but he will talk you through it because he came to my house to help me out.

did you do a rebuild on the carb?

good luck!!!!

 

Erm, where IS the idle screw?

Haynes has it in a place that it isn't?

 

Yep same problem here, when I had to adjust mine.

Your idle mix screw is centered in the left face of the carb bore.

To reach the idle speed screw you need a long handled screw driver. Lay it across the rats nest and in front of the oil cooler. The handle should rest between the last two rats nest 'hump' lines. The screw should be loctated about 1/2" below and in from the rear left side of the linkage. So with your screwdriver laying where it is, move it straight in and it should get to the scew.

It helps if you put a dab of caulk or grease on the end of the screwdriver so it'll kind of stick to the screw. Saves a lot of trouble having to reset it.

Sterling is the man, go to www.sterlingmetalworks.com and read his idle adjustment procedure.

 

So, the idle screw is the same as the mixture screw?

 

ya same side of the mixture screw, but on the right of it.

 

not to scare you, but thats how mine was acting with the crack in the rotor housing...