Carburetor question Stromberg 2bbl

[Jim 68cuda]

The accelerator pump on the Stromberg 2bbl carb on my 66 poly 318 Sport Fury is sticking in the up position. I tried installing a new one but have the same trouble. A stronger spring likely won't make a difference as it seems to take some effort to push it down. A buddy had the exact same issue with a Stromberg 2 bbl carb that is now on my 67 318 Belvedere wagon. In his case he solved the problem by installing an old used accelerator pump. I don't have an old one to try, but its clear that the pump works properly on the Belvedere but not on the Fury.
Has anyone else experienced this issue and is there a fix?

 

[C Body Bob]

I have a 68 318 I'm parting. Has the old 2 barrel Carter/Stromberg. If you need one for parts or a core let me know