Auto choke problems
Thread Starter
Racer
Joined: Jul 2016
Posts: 461
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From: Hoover AL
2017 C2 of Year Finalist
2016 C2 of Year Finalist
Auto choke problems
Had the '66 coupe almost a year. Nothing but carburetor problems since I had it, so had the holly four barrel rebuilt by an expert. Runs great except the damn auto choke does not open all the time, giving me hell in cold weather. After long warm up in the morning, the choke still does not open, causing rough driving problems. Is there a replacement auto choke kit available to solve the problem. New carb rebuild works great except for the old nemesis ..... the damn auto choke. Car is NCRS, so I need to keep a manual auto choke.
Safety Car
Joined: May 2014
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The choke rod adjustment should be checked first, this procedure is in the service manual. The other part in question is the manifold stove spring that controls the rod mentioned above.
These are very simple adjustments and that choke system is very reliable so you should be able to repair the problem.
These are very simple adjustments and that choke system is very reliable so you should be able to repair the problem.
Race Director
Joined: Apr 2005
Posts: 11,295
Likes: 2,150
From: Bowling Green, Kentucky
The choke rod adjustment should be checked first, this procedure is in the service manual. The other part in question is the manifold stove spring that controls the rod mentioned above.
These are very simple adjustments and that choke system is very reliable so you should be able to repair the problem.
These are very simple adjustments and that choke system is very reliable so you should be able to repair the problem.
But you should also temporarily disconnect the rod to the choke plate (top of carb) and make certain that the choke plate moves freely and does not bind or stick. If plate is free (as it should be) then the adjustments mentioned or replacement of the thermostatic coil in the intake manifold SHOULD solve your problem.Once correctly set, the choke doesn't often go bad on its own.......especially if the car is routinely driven.
Larry
Thread Starter
Racer
Joined: Jul 2016
Posts: 461
Likes: 118
From: Hoover AL
2017 C2 of Year Finalist
2016 C2 of Year Finalist
The choke rod adjustment should be checked first, this procedure is in the service manual. The other part in question is the manifold stove spring that controls the rod mentioned above.
These are very simple adjustments and that choke system is very reliable so you should be able to repair the problem.
These are very simple adjustments and that choke system is very reliable so you should be able to repair the problem.
Thanks for the info .... will pass this on to my "supposedly expert cab mechanic".
Team Owner
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From: Sitting in his Nowhere land Hanover Pa
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2015 C2 of Year Finalist
Dumb question is the heat riser exhaust valve on the passenger side exhaust working? If a cast iron intake is the hot slot open under the carb. And do you have the correct S/S baffle and carb gasket?
Thread Starter
Racer
Joined: Jul 2016
Posts: 461
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From: Hoover AL
2017 C2 of Year Finalist
2016 C2 of Year Finalist
Answers to questions. The heat exhaust value is working. Supposedly when they checked, the choke flap was working freely without sticking. That leaves the actuation rod and the heat sensitive spring to check. My feeling is that the heat activating spring is not working because on idle when the engine reaches operating temperature gets to normal, the choke remains closed. Thanks to all. This site is so full of useful information.
Race Director
Joined: Apr 2005
Posts: 11,295
Likes: 2,150
From: Bowling Green, Kentucky
Answers to questions. The heat exhaust value is working. Supposedly when they checked, the choke flap was working freely without sticking. That leaves the actuation rod and the heat sensitive spring to check. My feeling is that the heat activating spring is not working because on idle when the engine reaches operating temperature gets to normal, the choke remains closed. Thanks to all. This site is so full of useful information.
Larry
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Thread Starter
Racer
Joined: Jul 2016
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From: Hoover AL
2017 C2 of Year Finalist
2016 C2 of Year Finalist
I'm thinking that you are certainly correct. Went out on cool morning today, and it started fine using the auto choke. Let it get to normal operating temp, and then depressed the accelerator to lower rpm's. Then the thing goes wild .... running rough and tach acting like tumblers on a slot machine. Makes me think that the auto choke is working, but will not release when the motor gets to operating temperature. Closed garage door, and came back later when the motor had really gotten hot after shut down. It started and ran perfectly. Must be that the temperature operated spring is not working properly. Do you mechanical experts agree?
Team Owner
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From: Sitting in his Nowhere land Hanover Pa
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take a min and pull the cover off the spring and have a quick inspection of the spring. the cover is only pressed unto the spring base.
Racer
Joined: Dec 2015
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From: Los Angeles
I am also having an issue with the choke, I purchased a new spring, are there any pictures showing the correct position the rod should be in when attached to the spring and carb, mine when attached does not allow the choke to fully go off, I removed the rod and the choke is now off and my car is idling better. Thanks in advance for pictures. Ian
Team Owner
Joined: Mar 2003
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From: Greenville, Indiana
I'm thinking that you are certainly correct. Went out on cool morning today, and it started fine using the auto choke. Let it get to normal operating temp, and then depressed the accelerator to lower rpm's. Then the thing goes wild .... running rough and tach acting like tumblers on a slot machine. Makes me think that the auto choke is working, but will not release when the motor gets to operating temperature. Closed garage door, and came back later when the motor had really gotten hot after shut down. It started and ran perfectly. Must be that the temperature operated spring is not working properly. Do you mechanical experts agree?
If you've been driving it with the choke on, pull the dip stick and see if it smells like gasoline. If it does, change the oil.
Team Owner
Joined: Mar 2003
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From: Greenville, Indiana
FWIW to whoever cars. there was more than one choke spring released for the choke on Holley carbs. Depended on the engine, manifold and I think the carburetor. Don't remember but make sure you have the right one.
Team Owner
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From: Sitting in his Nowhere land Hanover Pa
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Funny you say that Mike the resto houses sell only one. Where can you find different ones.
Team Owner
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From: Greenville, Indiana
You'll also find there are quite a number of different rod configurations between the coil and the carb, depending on the application.
There is a much bigger world out there than just the Corvette world.
Team Owner
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From: Sitting in his Nowhere land Hanover Pa
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There appears to be only one for 1966. If you look across other years of GM car lines you'll see other options for the thermostatic spring and they will mount to the '66 manifold but will not work.
You'll also find there are quite a number of different rod configurations between the coil and the carb, depending on the application.
There is a much bigger world out there than just the Corvette world.
You'll also find there are quite a number of different rod configurations between the coil and the carb, depending on the application.
There is a much bigger world out there than just the Corvette world.