I have a '72 Demon 225 Slat six. It has the
Holley 1 barrel model 1920. I re-built it and
now it leaks where the accelerator pump shaft
comes out. I tried 2 pump diaphragms, and they
both leak. It didn't leak with the old one.
No parts seem to be damaged. Anyone have any
Ideas? Thanks.

faustbask@yahoo.com

I once had that same problem.What solved mine was thoroughly cleaning the accel.pump bore and I used some 320 fine paper. Recleaned all parts. If you have the leather type pump,soak it in fresh gas for a few hours then assemble. worked for me, hope it does for you.

MoparBrat63@aol.com

Mine has a rubber diaphragm pump with a flat shaft.
The only way for it to leak is for gas to get
past the diaphragm. The Diaphragm is part of the
gasket between the main body and the economizer
body. When I take it apart, I can see a ring
impressed in the gasket where it should be sealing
around the diaphragm, but apparently it's not.
I don't suppose there is any type of sealer that
can be used to create a better seal? This thing
has really got me stumped.

faustbask@yahoo.com

That is a stumper!My carb. is a BBS Carter so it just goes to show I was'nt paying attention to your carb make. I am reading my factory service manual and this is all it says for the Holley 1920 pump installation::Slide the pump diaphragm and stem into position in the carb.then install the pump return spring.Turn the carb.with bowl opening up then position the main well and equalizer body in the carb.and install screws.::Then it says in bold print,be sure the pump spring is correctly centered.I was going to say maybe a warped econo.body but,it does'nt leak with the old diaphraghm.Hmmmm...what's the chances of getting two defective diaphraghms.

MoparBrat63@aol.com

I had this exact same problem, and it was a warped econo. body. I think when I rebuilt the carb. the old varnish and residue was keeping it from leaking, and when cleaning this away it caused it to leak past the diaphragm.
Good luck.