Stalling issue

Discussion in 'Troubleshooting & Diagnosis' started by Anthonycfv, Jul 14, 2021.

  1. gmacheen

    gmacheen New Member

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    Thanks Mallard. I may just throw another carb on it just for kicks & giggles to see how the car responds.

    I'm convinced it has something to do with timing. I think I'll try slightly stiffer mechanical advance springs in my HEI distributor, to see if maybe the advance is coming on too soon causing an extra lean idle mixture??? I was also thinking about hooking the vac. can to ported vacuum to see how the car responds. Ported vs manifold vacuum seems to be an ongoing debate in many forums. Feel free to give me your opinion.
     
  2. berg2695

    berg2695 Veteran Member

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    Maybe the primary nozzles are dripping at idle because the throttle plates are cracked open more than stock because of the performance camshaft. This might cause an unstable idle. Maybe try richening the idle screws and lowering idle speed. The idle circuit may be too lean, covering for the nozzle drip richness. Also, is the pcv valve in place and working properly? Good luck. Hoping to hear good news.:)
     
  3. gmacheen

    gmacheen New Member

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    Berg2695, just out of curiousity, why do you ask about the PCV valve?
     
  4. berg2695

    berg2695 Veteran Member

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    The engine will ingest a small amount of air through the pcv system at idle, air that doesn't have to go past the throttle blades. That allows a bit smaller throttle opening at idle to help prevent the main nozzles from dripping. Anything you can do to minimize the throttle opening at idle will make for a more stable idle, especially with a performance camshaft. I've also heard of people drilling tiny holes in the throttle blades to keep the blade edge in the right place relative to the idle system slot in the bore. I have to admit, some of this is kinda theoretical to me. Others on here have WAY more practical experience. I learned a lot about carburetors from the book "ROCHESTER CARBURETORS" by Doug Roe. I highly recommend it!
     
  5. gmacheen

    gmacheen New Member

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    Great info, thanks!
     
  6. mallard

    mallard Veteran Member

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    Berg raises a good point, any "lean" condition when returning to idle could certainly cause a stalling issue, IMHO.
     

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