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Old 09-28-2020, 10:00 AM   #1
Harpkatt
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Default Idling high

With the idle adjustment screw backed as far as it will go, my engine is still idling a tad high. I recently retimed and re adjusted points but no change. The car runs fine and doesn't seem short on power,doesn't pop or hesitate like a vacuum leak.

It's bit more of a crash going into first gear than I would like.

I'm sure it's a simple fix,hoping it's a simple fix. Could this be a carb issue?
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Old 09-28-2020, 10:10 AM   #2
ryanheacox
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Default Re: Idling high

Most likely a carb issue, yes.

My engine idled a little high and I couldn't get it lower just like you. I took the carb off and saw that the throttle plate was tweaked ever so slightly in the bore keeping it from closing completely.

The fix was loosen the 2 screws, snap the throttle shut a few times until there was barely any light coming in around the plate and then tighten the screws back up.

Now it idles low and slow just like it should.
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Old 09-28-2020, 10:11 AM   #3
katy
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Default Re: Idling high

When the screw is backed out is the finger on the throttle arm hitting the stop on the carburetor body?
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Old 09-28-2020, 10:13 AM   #4
Patrick L.
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Default Re: Idling high

Which idle adjustment screw are we talking ? Mixture or speed ?

I'll assume speed, but,,,,

Have you tried disconnecting the throttle link at the throttle arm ?
Throttle shaft bushings could be bad.
Throttle plate may not be centered up in the bore.
Could be a vacuum leak.




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Old 09-28-2020, 12:09 PM   #5
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Default Re: Idling high

If you need any tips on doing a vacuum test, here's the thread where I talk about how I did mine:
https://www.fordbarn.com/forum/showthread.php?t=273571
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Old 09-28-2020, 01:20 PM   #6
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Default Re: Idling high

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Pull the linkage rod off the carb and hold the throttle shut. If the idle drops, your linkage is hung up somewhere.
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Old 09-28-2020, 03:18 PM   #7
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Default Re: Idling high

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Originally Posted by 1930-Pickup View Post
Pull the linkage rod off the carb and hold the throttle shut. If the idle drops, your linkage is hung up somewhere.



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Old 09-28-2020, 03:53 PM   #8
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Old 09-28-2020, 05:36 PM   #9
Kurt in NJ
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Default Re: Idling high

Worn throttle shaft, and sides of butterfly worn will make a higher than normal idle to have airflow across idle passage
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Old 09-28-2020, 06:50 PM   #10
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Default Re: Idling high

Remove the carburettor and back the idle stop screw right off till it is clear of its stop. At this point, it is the plate that is stopping it closing any further. Then loosen the two screws holding the throttle plate in the shaft. While holding pressure on the throttle arm in the close direction, tap the plate lightly with the handle of a screwdriver. If the plate is not quite right, this will move it to the correct position. This will make sure that the throttle is closing all the way. You will know when it is is right because the tiny hole in the throat of the carby at the float bowl side will be half open, half covered by the plate. Retighten the screws, reinstall and reset the idle speed. Likely, it will be good. All that said, if the shaft is loose in the body, all bets are off.
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Old 09-29-2020, 05:53 AM   #11
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Old 09-29-2020, 07:21 AM   #12
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Default Re: Idling high

Ok, will check linage, throttle shaft and butterflies. Vacuum test if I get past those steps.
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