idle too fast

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Jun 4, 2001 | 01:52 PM

rusty68

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Joined: Sep 2000

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idle too fast

i'm having trouble keeping my idle speed down-

after mashing the gas a few times, the accelerator return spring can't return the throttle linkage to the original position.

i thought i needed a stronger spring, but it didn't make any difference- so, i thought maybe the dashpot was worn out (original ford 2-barrel carb). i took the dashpot off- no difference.

with the engine running, i can pop the hood, and manually pull the throttle linkage back to it's original position, and the idle drops right down. it just requires a slight tug.

i was wondering if the spring that the throttle arm is riding on could be worn out. i didn't see how to replace it, as the arm seems to be riveted on.

(i finally did try a REALLY big throttle return spring, and it worked, but the spring was so big that it actually made it hard to push the gas pedal with my foot.)

any ideas? i'm sure it could probably use a new carb, but i hate to buy one just because i can't get the idle speed right.

thanks,
sam
'68 f100 360 FE

Jun 4, 2001 | 01:58 PM

dre

Senior User

Joined: Oct 2000

Posts: 219

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From: Richmond USA

idle too fast

Try checking your fast idle cam on the opposite side of the carb.
It might need adjusting out some. Also try spraying the linkages with carb. cleaner.

Dre'
1978 F-150, 460ci(750cfm,Edelbrock Performer,Dynomax Ceramic Coated headers,etc.)Auto-C6,3:70.1 - 9" Posi.

Jun 4, 2001 | 03:28 PM

dzjammer

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Joined: Dec 2000

Posts: 435

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From: Nebraska Farm

idle too fast

It sounds like something is binding in the linkage. make sure nothing is bent or out of place. look for fresh scratch marks on parts that shouldn't have scratces. also, make sure the pedal is free and not sticking to the floor mat.
Dave,
79 F-150 4x4, 390 w/C6, Edelbrock carb, 33X12.50 never will be finished.

Jun 6, 2001 | 05:01 AM

MSTRAWN

Senior User

Joined: Aug 1999

Posts: 166

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idle too fast

Another thing to check would be the fit of the throttle shaft itself. If the carb is original it may have worn into the carb body to such an extent that it binds when you take your foot off of the pedal. The wear will be most apparent on the linkage side. Mike
:->
1977 F-100
300 I-6 / C-4 (soon to be AOD)
Offy C intake w/Edelbrock 500CFM
Hooker Ceramic coated headers w/duals, turbos, tips, and 02's
MSD6A w/Blaster Coil
Headlight relay system (Delanty style)
Overhead Mount FM-CD etc.
R-134 A/C system (I'm cool)

Jun 6, 2001 | 09:00 AM

73Custom

Postmaster

Joined: Apr 2000

Posts: 2,838

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From: SD

idle too fast

[font color=red size=2]Disconnect the gas pedal shaft from the carb, then run the throttle a few times and see if it still sticks, then you know if it's in the carb or the gas pedal. If it still sticks then I would assume it needs a good cleaning, spray the linkages with carb cleaner, also spray the butterflys inside the carb, they could have a build-up that is preventing them from closing. If cleaning doesn't help then the carb is worn and probably needs replaced.

Marty

"Cleverly Disguised as a Responsible Adult"[/font]

Jun 6, 2001 | 10:14 PM

weldman

Fleet Mechanic

Joined: Feb 2001

Posts: 1,290

Likes: 15

From: Toronto, Canada

idle too fast

hey, I'm sometimes have the same problem.

See my post called '351m choke adjust' on page 1.
I lubed mine up, but i still have it sticking!
Good luck!

https://www.ford-trucks.com/dcforum/User_files/3ae0a7e34062b4ad.jpg https://www.ford-trucks.com/dcforum/User_files/3ae0a7b33fe32dbb.jpg
1978 F250 4x4 - 351M
Don't crush them, restore them!

Jun 8, 2001 | 06:02 AM

gadams

Senior User

Joined: Feb 2001

Posts: 158

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idle too fast

I was having the same problem with my 390 and found that it was because the throttle plates were binding in the bores. You can tell this is happening by taking the carb off and looking through the carb throats... you shouldn't be able to see any light around the edges of the plates. I had to loosed the screws a little bit and open and shut the throttle all the way a few times, re-tighten the screws and it was good as new.

Greg
67 F100 CCS 390 cruise-o