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Old 06-04-2019, 08:21 AM   #1
ling102
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Default Erratic idle

I have a 1951 Ford 2 door sedan, flathead 8, standard trans.The car has an electric fuel pump.
The idle is erratic. Any thoughts on smoothing the idle out?
Thanks guys.
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Old 06-04-2019, 08:53 AM   #2
Mart
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Default Re: Erratic idle

Yeah. adjust the mixture, the idle screw and the timing. Make sure the carb matches the distributor. Make sure the diaphragm in the distributor works, make sure the points and condenser are good. Make sure the pump output is not too high pressure for the carb. Make sure there are no vacuum leaks around the carb and manifold and vacuum fittings for wipers etc.

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Old 06-04-2019, 01:56 PM   #3
supereal
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Default Re: Erratic idle

Be sure to check the throttle shaft in the carb for any play due to wear. This allows vacuum leakage, and interferes with the seating if the throttle plate. It is possible to have bushings installed to fix the problem, but usually carb replacement is less expensive. Also look for distortion of the mating surfaces of the carb body. This occurs when the screws are overtightened, and can result in leakage of air or fuel. Unscrew the idle needles and look for evidence of damage. Any of these conditions will affect smooth idle.
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Old 06-04-2019, 02:15 PM   #4
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Default Re: Erratic idle

If the throttle shaft is sloppy and leaking vacuum, these carbs never had bushings originally, and the shafts are what wears out more than the holes in the base. This is usually repaired with oversized throttle shafts which are available from Charlie ny on the Ford Barn. AKA: Charlie Schwendler (716)662-9159 cas5845@yahoo.com


Sal
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Old 06-04-2019, 02:31 PM   #5
ling102
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Default Re: Erratic idle

I appreciate the time that everyone took to provide information and expertise in helping me with the idle problem with my car. I hope to be able to work on my 51 this weekend.
You guys are awesome! Thanks again.
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Old 06-04-2019, 03:27 PM   #6
4dFord/SC
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Default Re: Erratic idle

Wasn't he a member of Monty Python?
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Old 06-04-2019, 06:27 PM   #7
19Fordy
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Default Re: Erratic idle

Plug wires and plugs are good?
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Old 06-05-2019, 08:25 AM   #8
big job
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Default Re: Erratic idle

You need a vacuum gauge they are cheap enough: As said above throttle shaft & bushings, point gap closed up, weak condenser, leaking valves, dirty idle passage's or
in general a dirty carburetor; did this just start? When was the last time it ran smooth?
Did it run fine with electric pump before or did you just install elec. pump? could be high
pump pressure these only need 2-3 lbs. if more pressure you would be 'drowning' it to
a point it would hardly idle at all. Then the pest, a leaking power valve ? Poor dist. cap
and or rotor? So the vac. gauge still rules. GET this; back in high school when these
V8's ruled the roads, we had a couple on test stands. diagnosis: the teacher would draw lines with a lead pencil inside of the distributor cap which drove the kids bonkers.
One really couldn't see said lines. I was the only one grown up in my fathers shop. So
I remember taking the cap off drop on the floor. whoops sorry, put another cap on then
it ran like a champ. And I did not get a A for that one cause my father taught me about
carbon tracks! sam
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Old 06-05-2019, 02:19 PM   #9
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Default Re: Erratic idle

Quote:
Originally Posted by 4dFord/SC View Post
Wasn't he a member of Monty Python?

That's a good one!!
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Old 06-18-2019, 10:19 AM   #10
ling102
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Default Re: Erratic idle

You guys are awesome! Thanks again for all the replies.
I am hoping to work on this soon. when I have the remedy I will post!
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Old 06-18-2019, 12:31 PM   #11
joe 1950
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Default Re: Erratic idle

and a compression test will tell you if there’s a valve problem
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Old 06-18-2019, 02:56 PM   #12
Charlie ny
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Default Re: Erratic idle

X3 Sal and superreal
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Old 06-18-2019, 10:54 PM   #13
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Default Re: Erratic idle

Charlie........Thumbs Up ...
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