Holley secondaries sticking open. Where to look first?

This thing is freshly rebuilt, and tuned to RUN, but today, I stomped the pedal to prime it before starting it, and the throttle is binding as it crosses into the secondaries, and then sticks open.

Disconnected the throttle cable, ran it by hand, and looked around, but I see nothing obvious.

Where should I start looking?

 

Did you disassemble the throttle shafts and butterfly's when you rebuilt it ?

 

Don't remember. I don't think so. I think I just blew out the passages and sprayed cleaner in the body. I dunked the bowls and metering blocks into the cleaner ate the shiny coating off and left a gray chalky residue, so I didn't do the body.

 

May have oxidation in the shafts. Might need to remove the carb and check it out. I like PB blast as a final coating on linkages and the shaft my self.

 

Throttle blades catching on the gasket or mounting flange? Could also be an issue with the choke/high idle linkage.

 

I had to grind some off of my spacer because on the pass side the belcrank/spring or rod rubbed on the spacer and could rub on manifold deppending on manifold.

 

Just took it apart. With the bowls off (or with primary bowl on and secondary off) it works fine, nice and smooth.

Accel pump on secondary seems to be pumping smoothly. Releases smoothly.

Put it back together, and immediately binds. Even before I put the secondary bowl bolts in, and just put it together and hold it there by hand, it binds when it rolls over to secondaries.

I am pretty much stumped.
And this is with the carb removed from the car, to eliminate any other items rubbing and binding with it.

 

You keep playing with it. It will reveal it's self.. Has it dropped or been laid on the table on it's linkages?

 

so when the secondary accelerator pump lever is put into the mix is when it binds up?

 

Secondary accel pump seems to be the issue. Feels fine when I manually activate it, but when it is on the carb, the plates stick open.

The plates should snap back even if the accel pump sticks, though...

 

just a shot in the dark, is the bolt with the spring that pushes on the pump lever loose and some how deflecting and catching on something?

 

try replacing the accelerator pump cam with another one just to see if thats what is jamming it up. i just went and looked at my carb and thats the only thing that i can see that could cause that problem

 

OK, figured it out. Not sure why it all of a sudden became an issue, as I have been driving this as it was for the past 6 months.

The cam on the secondary side was mounted in the wrong hole, so it was WAY too steep/tall. So when it went all the way up through the secondaries, it was binding up at the top and making the carb stick open. Basically, the finger that rides the cam was landing on a flat side of the cam and holding everything open, not letting it slide back to idle.

I moved the screw to the other hole in the cam mounting bracket, and now it goes through the entire range of motion without binding. This cam only has one screw hole, I think it is the most aggressive one in the pack. I guess in the first hole I was in, I was resting on the middle of the cam, not on the flat before the cam was supposed to start moving the pump.

Again, not sure why it worked OK in the other screw hole for the past 6 months and just now started to bind. And trust me, I did plenty of full throttle driving while I was tuning the carb, and never had that binding or sticking.

 

Maybe while driving when coming off the throttle hard vac helped pull it close????
At least it was an easy fix

 

What type of return spring setup do you have? What color is the secondary pump cam?