General Category > Quadrajet Carb Talk and Tips

Setup Questions

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Chief_Wiggum:
Finally had some time to work on this yesterday.  Tore the carb apart and replaced the DCRs with .043"s.  Also checked on the mixture screws.  The replacements that Cliff sent me do not seat all the way.  The threads bottom out before the needle will close the passage.  I put the stock ones back in and those seem a lot better.  You can see in the picture how far they screw in.  From what I can figure out, the carb must be getting all of it's idle fuel from the transfer slot?  Is that even possible?

Now showing AFRs of 13.0 - 14.0 at idle.  However, I have the mixture screws in as far as they will go and I cannot lean it out any more.  Idle speed with the .110" bypass air ports is ~1000rpm.  The primary butterflies are all the way closed.

Also, another oddity.  This carb has no timed vacuum ports.  All the vacuum ports are manifold vacuum.  When I had it off I verified that the port usually used to connect the distributor (driver's side front of carb) comes out below the butterflies.  Is this normal?

I think my next steps will be to block off the bypass air and see if I can lower the idle.  Will that result in a leaner idle mixture?  Any tips on what I should do with the vacuum port?

v737d:
I can't help you with the idle or needle seats, but I can tell you your distributor vacuum source should be above the butterflies=no vacuum at idle.

Cheers

Chris

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