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Author Topic: EXTREMELY High Idle - Edelbrock Carb  (Read 12742 times)

Offline VeeTwin60

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EXTREMELY High Idle - Edelbrock Carb
« on: April 18, 2010, 05:44:33 pm »
Hi Guys - I've got an #1406 Edelbrock carb (electric choke) that I just bought and installed.  It is on an '86 Custom Deluxe with a 350 cu.in. and TH350 trans.

After the install, I started it for the first time and the idle is around 3500 RPM.  I cannot figure out why.  I've disconnected the throttle and kickdown cables.  I've backed the idle adj screw all the way out.  I've made sure no linkage is stuck.  I've manually opened the choke butterfly plate.  Nothing works.  Please help!
« Last Edit: April 18, 2010, 05:59:06 pm by VeeTwin60 »
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Offline VileZambonie

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Re: EXTREMELY High Idle - Edelbrock Carb
« Reply #1 on: April 18, 2010, 06:13:06 pm »
Did you hook up the brake booster hose to the back of the carb or at least plug that port?
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Offline HAULIN IT

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Re: EXTREMELY High Idle - Edelbrock Carb
« Reply #2 on: April 18, 2010, 09:09:24 pm »
What intake is on the engine...Spread bore flange? Lorne 
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Offline Blazin

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Re: EXTREMELY High Idle - Edelbrock Carb
« Reply #3 on: April 18, 2010, 09:39:30 pm »
Edeljunk! Thats why!
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Offline Irish_Alley

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Re: EXTREMELY High Idle - Edelbrock Carb
« Reply #4 on: April 19, 2010, 01:38:56 am »
like vile said sound like a vacuum leak
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Offline VeeTwin60

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Re: EXTREMELY High Idle - Edelbrock Carb
« Reply #5 on: April 19, 2010, 04:09:46 am »
I've hooked up the brake booster to the back port.  I've got the PCV valve to the front port.  I've got the distributor/trans hooked up to the driver side 3/16" port, and plugged the other 3/16" port.
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Offline Irish_Alley

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Re: EXTREMELY High Idle - Edelbrock Carb
« Reply #6 on: April 19, 2010, 05:11:06 am »
check your seal between the carb and intake
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Offline greenmonster

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Re: EXTREMELY High Idle - Edelbrock Carb
« Reply #7 on: April 19, 2010, 05:48:05 am »
Did you check the fast idle screw.
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Offline VeeTwin60

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Re: EXTREMELY High Idle - Edelbrock Carb
« Reply #8 on: April 19, 2010, 08:02:27 pm »
Quote from: greenmonster on April 19, 2010, 05:48:05 am
Did you check the fast idle screw.
How embarrassing.  I didn't even think about that.  Thanks.
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Offline HAULIN IT

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Re: EXTREMELY High Idle - Edelbrock Carb
« Reply #9 on: April 19, 2010, 09:15:26 pm »
Quote from: HAULIN IT on April 18, 2010, 09:09:24 pm
What intake is on the engine...Spread bore flange? Lorne 
I just checked in to see how you've made out & noticed you haven't answered this. Do you have a spread bore (q-jet) type intake or a square flange (Holley) type?
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Offline beastie_3

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Re: EXTREMELY High Idle - Edelbrock Carb
« Reply #10 on: April 20, 2010, 01:37:22 pm »
I believe you can download the tuning instructions directly from Edelbrock also.
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Offline VeeTwin60

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Re: EXTREMELY High Idle - Edelbrock Carb
« Reply #11 on: April 20, 2010, 06:25:49 pm »
Quote from: HAULIN IT on April 19, 2010, 09:15:26 pm
Quote from: HAULIN IT on April 18, 2010, 09:09:24 pm
What intake is on the engine...Spread bore flange? Lorne 
I just checked in to see how you've made out & noticed you haven't answered this. Do you have a spread bore (q-jet) type intake or a square flange (Holley) type?
Square.
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Offline HAULIN IT

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Re: EXTREMELY High Idle - Edelbrock Carb
« Reply #12 on: April 20, 2010, 10:44:14 pm »
What type of carb did you have on it before this install? Studs or bolts just a hair too long (running out of threads)? Did you move or change anything like accessory brackets or anything else that bolted to the intake while you were doing the carb swap? I agree with the others...likely your hunting a vacuum (air) leak. Lorne 
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Offline VeeTwin60

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Re: EXTREMELY High Idle - Edelbrock Carb
« Reply #13 on: April 22, 2010, 06:56:09 pm »
It was the fast idle screw.  Look a few posts up. :)
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Offline VileZambonie

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Re: EXTREMELY High Idle - Edelbrock Carb
« Reply #14 on: April 22, 2010, 10:40:50 pm »
when the choke is open you should be off of the fast idle cam. You may want to double check it's operation.
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74 GMC, 75 K5, 84 GMC, 85 K20, 86 k20, 79 K10
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