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Discussion Starter · #1 ·
Hi everyone,

Working on a 1985 GMC c2500 with a sbc 350 engine. I've been trouble shooting a really rough idle that will just stall out and die. I took the carb off and noticed this piece on the intake manifold that was a little crooked (looks like it's missing a bolt). I attached a picture below, does anyone know what this is for? Can I just add a second bolt to the bottom to plug the hole?
 

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Not even close bogie!
it’s the choke stove adaptor on an edelbrock intake.
installed upside down.
for a divorced choke carb.

pic here.


 

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Discussion Starter · #4 ·
I tightened it up and replaced the carb and now it's backfiring out of the carb. Any ideas why? Double checked and I don't have any crossing spark plug wires or anything. Was running fine last week besides dying at idle.
 

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Not even close bogie!
it’s the choke stove adaptor on an edelbrock intake.
installed upside down.
for a divorced choke carb.

pic here.


So it is, need to slow down and really look or maybe time for new glasses.

Bogie
 

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Discussion Starter · #7 ·
Interesting, well that's the machine shops fault he installed that onto the intake. What is this used for? Can I flip it over and tighten it down to stop intake leak? I have an electric choke on the carb by the way.
 

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Interesting, well that's the machine shops fault he installed that onto the intake. What is this used for? Can I flip it over and tighten it down to stop intake leak? I have an electric choke on the carb by the way.
That should not present as an intake leak there should be no connection with that cavity and any vacuum source to the fresh charge part of the intake. That is a hot spot to either mount a divorced choke’s thermo coil or as a heat source for an integrated with carb thermo coil.

Its possible that a bolt hole penetrates an intake passage and leaks air so this thing should be secured. If the Edelbrock carb has a choke it’s most likely either manual or electric so for your application the exhaust hot spot serves no functional purpose so just close it as designed.

Bogie
 

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Hi everyone,

Working on a 1985 GMC c2500 with a sbc 350 engine. I've been trouble shooting a really rough idle that will just stall out and die. I took the carb off and noticed this piece on the intake manifold that was a little crooked (looks like it's missing a bolt). I attached a picture below, does anyone know what this is for? Can I just add a second bolt to the bottom to plug the hole?
If it’s sucking vacuum, just put a bolt in it, if not don’t worry about it
 

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You need to do a vacuum leak investigation. With the engine idling, take off the air cleaner and plug any vacuum hoses. Them place a hand over the carb air horn. If the idle smooths out and picks up, you have a vacuum leak.
 

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When I converted from hot air to electric choke on my Quadrajet there was a port on the front of the choke housing that had to be capped. IIRC this port did draw vacuum, which is why the cap was needed. Maybe the cap is missing on your carburetor.

If you look at the docs for one of the electric choke kits it shows the port that must be capped.
 
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