Racing Fuel Systems

Had this carb on the dyno yesterday. Secondaries only stick when the motor is running and after the secondaries have been opened. They can be pushed shut while the engine is running with little effort. They are lubed with moly lube and are free moving. Not sticky in any way and cannot be made to stick when the motor is not running. It's like vacuum is causing them to hang open. This is the first time I have worked with one of these carbs. Any ideas?

The rod to the secondaries has to be installed the correct way. The secondary return spring has to be correct. Other than that no idea

Thank you for responding. All seems to be in order as far as I can tell.

Have not seen the linkage on that model, but thick base gasket/warped intake flange/overtightened bolts can cause sticking.

In the picture I can't see if the secondary spring is attached to the pin on the baseplate. But I'm sure you have already checked that. If you unhook the secondary rod the secondary shaft should SNAP back closed easily when opened. The secondary shaft could be slightly warped or the butterflies are not clocked ( aligned ) properly.
I learned a lesson on one of my first carb restoration for my brother . It was a quadrajet that i installed bushings in the primary shaft. I gave the carb back to him to install. Being a farmer he torqued the carb down tight. He started the car and let it warm up. The throttle started sticking slightly. It just didn't return to idle always. I could loosen the flange bolts and it was fine. The lesson was I left those bushings on the tight side.
Any ways what I'm trying to say is if things are a little tight it could be worse when heat is applied

GTO Geoff
Have not seen the linkage on that model, but thick base gasket/warped intake flange/overtightened bolts can cause sticking.
He is correct again

It's an odd deal. Only sticks when engine is running. As soon as the motor is shut off it doesn't stick.