Idle question
Thread Starter
Burning Brakes
Joined: Jul 2016
Posts: 769
Likes: 123
From: Heerde Gelderland
Idle question
Hi guys,
Today was the first day I had a long drive with the c2 and I noticed that when the fast idle cuts out the idle will go to 450 or so. When I am parkerd it will run 450 but of course that's t too low, and while driving it will die when you brake and the clutch is fully pressed. As soon as you give a little throttle it runs great and won't die.
The car also gives little humbs when you drive a constant rpm let's say 1800 rpm in first gear, if you try to keep it at that rpm constant it will humb a little.
Ps the first 10 minutes of driving when the choke is still engaged the car runs absolutely great without any mistake, and no humbs at all
I know the idle should be around 750 but I am not a carb guy so what's the best way to approach, I have a 1966 327 300 and the carb is a holley with electric choke.
Thanks!
Today was the first day I had a long drive with the c2 and I noticed that when the fast idle cuts out the idle will go to 450 or so. When I am parkerd it will run 450 but of course that's t too low, and while driving it will die when you brake and the clutch is fully pressed. As soon as you give a little throttle it runs great and won't die.
The car also gives little humbs when you drive a constant rpm let's say 1800 rpm in first gear, if you try to keep it at that rpm constant it will humb a little.
Ps the first 10 minutes of driving when the choke is still engaged the car runs absolutely great without any mistake, and no humbs at all
I know the idle should be around 750 but I am not a carb guy so what's the best way to approach, I have a 1966 327 300 and the carb is a holley with electric choke.
Thanks!
Le Mans Master
Joined: Apr 2005
Posts: 6,350
Likes: 423
From: Seattle Area WA
It sounds like your curb idle screw needs a slight adjustment. Just go to youtube search holley curb idle adjustment. You need about 1/2-3/4 turn on it to bring idle up to 750-800 rpms.
Racer
Joined: Jun 2013
Posts: 337
Likes: 27
From: Fremont CA
Maybe also check your return spring. My car would idle inconsistent high and at times when coming to stop. Low(500~600) when the car was parked after driving -> restart. I reduced the length on mine to minimize any free play and it worked so far for the high idle and starts up fine after parking.
Thread Starter
Burning Brakes
Joined: Jul 2016
Posts: 769
Likes: 123
From: Heerde Gelderland
Okay I turnend the curb idle screw clockwise 3/4 of a turn, it didn't seem to do so much, it did idle a little higer I think. Didn't had the time to test with engine running and turning the screw at the same time, just turned the screw 3/4 and went for a drive, after 5 minutes idle dropped pretty low again did not die allthough.
Give it some more turns or start to look for other things?
Give it some more turns or start to look for other things?
Last edited by Twan Sloot; Mar 31, 2017 at 12:17 PM.
Thread Starter
Burning Brakes
Joined: Jul 2016
Posts: 769
Likes: 123
From: Heerde Gelderland
I kind of get the idea it runs to lean because with the choke engaged it runs absolutely fine and drives fine, and when the choke cuts out after 5 minutes it only runs good when you have the throttle pressed (even a little is enough).
Nowhere man, you are talking about the vacuumadvance I suppose, how to check? the line from carb to distrubutor is fine.
Nowhere man, you are talking about the vacuumadvance I suppose, how to check? the line from carb to distrubutor is fine.
Last edited by Twan Sloot; Mar 31, 2017 at 12:28 PM.
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Melting Slicks
Joined: Apr 2015
Posts: 3,081
Likes: 1,130
From: NEW YORK
Okay I turnend the curb idle screw clockwise 3/4 of a turn, it didn't seem to do so much, it did idle a little higer I think. Didn't had the time to test with engine running and turning the screw at the same time, just turned the screw 3/4 and went for a drive, after 5 minutes idle dropped pretty low again did not die allthough.
Give it some more turns or start to look for other things?
Give it some more turns or start to look for other things?
Thread Starter
Burning Brakes
Joined: Jul 2016
Posts: 769
Likes: 123
From: Heerde Gelderland
, but I ran out of time.And it started raining
Team Owner
Joined: Feb 2003
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From: Sitting in his Nowhere land Hanover Pa
2024 C2 of the Year Finalist - Unmodified
2015 C2 of Year Finalist
You have the vacuum Advance can that can leak or your intake gasket could have a leak or the carb gaskets. If you have power brakes that could be anther source. Plenty of problem areas but should take less then 10 mins to figure out
Team Owner
Joined: Aug 2007
Posts: 58,061
Likes: 7,145
Army
Snug down the carb mounting bolts and any screws that hold the carb body together (WCFB or AFB). An unlit propane torch passed around likely leak points with the engine running will show up a leak if the idle increases at some area...
Le Mans Master
Joined: Feb 2014
Posts: 8,897
Likes: 5,436
From: Richardson Texas
Thread Starter
Burning Brakes
Joined: Jul 2016
Posts: 769
Likes: 123
From: Heerde Gelderland
Will update tomorrow
Thanks!
Thread Starter
Burning Brakes
Joined: Jul 2016
Posts: 769
Likes: 123
From: Heerde Gelderland
Thread Starter
Burning Brakes
Joined: Jul 2016
Posts: 769
Likes: 123
From: Heerde Gelderland
Safety Car
Joined: May 2014
Posts: 3,783
Likes: 655
Is this a problem that just started and the carburetor and adjustments were fine before. How old is the fuel in the tank.
The proper method to set the A/F screws is the get the engine good and hot and set the idle speed at your 6-700RPM then adjust the A/F emulsion screws to get the highest vacuum or idle, keep the screws on both sides approx the same turns out.
The proper method to set the A/F screws is the get the engine good and hot and set the idle speed at your 6-700RPM then adjust the A/F emulsion screws to get the highest vacuum or idle, keep the screws on both sides approx the same turns out.
Thread Starter
Burning Brakes
Joined: Jul 2016
Posts: 769
Likes: 123
From: Heerde Gelderland
Is this a problem that just started and the carburetor and adjustments were fine before. How old is the fuel in the tank.
The proper method to set the A/F screws is the get the engine good and hot and set the idle speed at your 6-700RPM then adjust the A/F emulsion screws to get the highest vacuum or idle, keep the screws on both sides approx the same turns out.
The proper method to set the A/F screws is the get the engine good and hot and set the idle speed at your 6-700RPM then adjust the A/F emulsion screws to get the highest vacuum or idle, keep the screws on both sides approx the same turns out.
Edit: forgot to mention the fuel is 7 months old, filled it up when it arrived with 98.
Last edited by Twan Sloot; Mar 31, 2017 at 04:31 PM.
Safety Car
Joined: May 2014
Posts: 3,783
Likes: 655
Get it good and warm and go through the idle adjustment mentioned above. It's a pretty standard procedure that is used when a engine is tuned up. Take a few minutes and make sure the dwell and timing is good, gotta start there.
FWIW, to set the idle speed on my 1967 300hp engine the idle speed screw is usually turned approx 3/4-1 turn after contact which yields approx 650rpm. If you are way off that it's possible there is a problem with the carburetor.
FWIW, to set the idle speed on my 1967 300hp engine the idle speed screw is usually turned approx 3/4-1 turn after contact which yields approx 650rpm. If you are way off that it's possible there is a problem with the carburetor.