Need help with secondary on stock carb.

Looking for any info/exp. on fixing the secondary. It opens but not all the way. I'm gunna check for vacuum leaks. Has anyone had the diaphram tear or has seen this happen? Just looking for pointers. 86 b2000 5spd all emissions still there.

Ok, more info. I sprayed a whole can of carb cleaner at all the vac lines and around the carb and manifold. nuttn. when i hold it full throttle and look down at the secondary it only opens maybe half way then starts to bog and some fuel mist/fog collects at the top of the opening to both barrels. I took it apart to fix a clogged idle jet a few weeks ago. Could it be an o-ring inside that needs replaced? any info is appreciated. I'm thinking of buying another carb and rebuilding it for now. I am going to try and make the secondary mechanical like the guys do to the 4 barrel rx7 carbs. I will keep you guys posted. And take pics if I can figure out the mech secondary deal.

You'll never see the secondary open all the way!
Because it's vacuum operated, it only opens fully under load.
Without load, you can snap the throttle and get it to begin opening, but when the rpm's come up, it will start to close again.
If you see it start to open, it's working fine.

hmm. The fuel filter is only a month old but it might it after all. thanks for the reply. If I hold it to the floor it bogs.

ok, pulled the air horn. replaced the o-ring I didnt replace when I clean out the idle jet. Cleaned the bowl out real good. New fuel filter. Put back together and took for a drive. No real change. When I got home pulled the ebrake and floored it. It went up to 4000 then slowly came down to 3000 and held steady there at 3000. Blue/black smoke. I have seen one of these motors hit 8000 sitting still. Maybe my cats are plugged up some. I got it up in the air cooling off now to take care of them next. Will keep you guys posted.

HA HA it was the cats. I gutted them and now this truck rips!