Carb rebuild

[Acoldtruckproject]

So I recently rebuilt the rochester 4mc on my 72 c10 with a 350. Now that I have it back on the truck and running, the idle rpms are twice what they should be and the idle adjustment scews seem to have no noticiable effect. I know I'm going to have to pull it off and go through it again, Im just curious if anyone knows the best place to start looking as to why this is happening.

[DT1]

Before you tear it apart, check the coil spring on the secondary throttle plate shaft. It it's not wrapped tight enough, the secondary plates will be slightly open and will cause it to run up.

[Wrenchbender Ret]

Check the fast idle cam to make sure it is dropping down when the choke opens. Back out the idle speed screw. It may have been turned in to compensate for poor running.