rough idle when cold

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  #1  
Old 11-13-02, 01:38 PM
honda86
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rough idle when cold

I have an 86 accord lx. the car has a carburetor and when i start the car in cold weather, it idles extremely rough and also drives like it is gasping for air. It will die if I don't get the rpms up at stops. As soon as the car runs for a couple of minutes, the fast idle kicks in and the problem is alleviated due to increased rpms. After the car heats up to the point where the cooling fan kicks on, the condition goes away. Please note this only happens in the late fall and winter when the temp is less than 50.I think the choke valve is closing and opening incorrectly but I would like another opinion.
 
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  #2  
Old 11-13-02, 02:35 PM
Joe_F
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What do you observe with regard to the choke operation? Mileage?

Has the carburetor been rebuilt? These are pesky carburetors not worth bus fare when they get old...
 
  #3  
Old 11-13-02, 02:57 PM
honda86
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i am not sure what you are asking. the car has 185k miles and as far as I know it is the original carburetor.
 
  #4  
Old 11-13-02, 03:57 PM
davidf
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vacuum break diaphram leaking or the vacuum break needs adjusting.
 
  #5  
Old 11-14-02, 04:44 PM
honda86
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when you refer to vacuum break, i'm not sure what you are referring to. Is it the choke opener diaphram which moves in relation to coolant temp. If not, what are you referring to? thanks a lot
 
  #6  
Old 11-14-02, 05:00 PM
Joe_F
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185k=tired carburetor..due for a rebuild. These are pesky to do and it takes someone with a good deal of kwowledge to get them right.

A vacuum break is also called a choke pull off. It is a vacuum operated diaphragm that controls the opening of the choke flap.

Start the vehicle stone cold first thing in the morning and tell us how the choke operates.

That's where we are going with this...
 
  #7  
Old 11-14-02, 05:58 PM
davidf
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The second you start the car the choke is closed tight for a very rich air/gas mixture since no air can get past the choke plate.After the car starts thanks to the rich mixture ,the choke plate opens just a hair to let some air past the choke plate so the car will be able to idle but the air/fuel mixture is less rich.There is a rod linkage that is on the side of the carb and it moves up the rod to perform the vacuum break of moving the choke plate.This rod is connected to a round vacuum diaphram mounted on the carb. and the diaphram has a vacuum hose connected to it so when vacuum is applied the rod is pulled back because vacuum pulls a plate inside the diaphram and the rod is connected to the plate and by linkage to the choke plate by rod,it opens the choke plate according to spec in fractions of an inch.Somtimes there are two or three vacuum diaphrams which moves the choke plate in steps for better post starting.
 
  #8  
Old 11-15-02, 09:43 AM
honda86
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thanks guys. I thought this was the problem. I will go in this weekend and see what is happening.
 
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