1.4 carb rough idle after motor rebuild

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jacquesdejager21
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1.4 carb rough idle after motor rebuild

Post by jacquesdejager21 » Mon Jun 25, 2018 1:24 pm

Hi guys,my buddy and I overhauled his 1.4 carb citi engine last week after it burst a water pipe and overheated.we started it up yesterday and it runs fine with the choke out,but once you push the choke in it idles rough/uneven..like a car with a race cam?any idea of what can cause this?

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Re: 1.4 carb rough idle after motor rebuild

Post by missioner » Mon Jun 25, 2018 1:38 pm

Timing or air leak.

Go back and check your work. You have made a small mistake and finding and rectifying this will solve your problem.

I think it's most likely a vacuum leak.
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Re: 1.4 carb rough idle after motor rebuild

Post by VAG Fan » Mon Jun 25, 2018 1:46 pm

The choke wouldn't compensate for bad timing, IMHO.

So, agreed on the vacuum leak. The engine is drawing unwanted air into the intake at some point, causing it to run too lean. By closing the choke, you're compensating the leak by throttling the air and adding more fuel.
Basically you need to check all the points where air can be (wrongly) drawn in.
... Carburetor baseplate, check for any cracks in the rubber, and for correct mounting
... Fitment of all vacuum lines and brake booster line
... Any gaskets on the intake side (did you have the intake manifold off the cylinder head?)
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jacquesdejager21
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Re: 1.4 carb rough idle after motor rebuild

Post by jacquesdejager21 » Tue Jun 26, 2018 6:21 am

Hi,thanks for all the info.we had the intake off to replace the gasket and the gromet for the water port between the head and the intake.I will have a look at the vacuum lines,hope that is the problem.

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Re: 1.4 carb rough idle after motor rebuild

Post by jacquesdejager21 » Thu Jun 28, 2018 5:55 am

Checked all vacuum lines,no damaged or leaking pipes..so will strip this weekend and replace gaskets and base plate

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Re: 1.4 carb rough idle after motor rebuild

Post by jacquesdejager21 » Thu Jul 05, 2018 5:28 pm

Hi guys,so we replaced the intake gasket,all vacuum lines and the base plate of the carb.Also cleaned the carb with carb cleaner and blew out with air,but still it idles uneven/rough and when it idles it doesn't stay constant on a rev...any other stuff i could check?

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Re: 1.4 carb rough idle after motor rebuild

Post by Ashveer03 » Thu Jul 05, 2018 7:09 pm

Check if the idle solenoid is working and that the earth strap from the carb to tappet cover is connected.

Had this issue recently, this car idled with the idle solenoid not working but very poorly.

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Re: 1.4 carb rough idle after motor rebuild

Post by panic-mechanic » Thu Jul 05, 2018 9:36 pm

or just make it a little richer by turning the mixture screw out and see if it helps.
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