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11/26/2018 9:45 PM  #1


Autolite 4100 "ECD" installed on 289 Coupe.........Troubles

Hi folks, I dont know if I forgot to push submit or my first posting was removed (?) either way :

I fully restored a ECD with 1.06 venturi, sodium blasted, washed, blew out all ports with carb cleaner and compressor.....this thing is mint, even put on Shaft Bushings to ensure tight seals, yet Im Getting High Idle........cant have it drop less than 1000RPM!!!!???

been doing a lot of reading and much to my surprise, many have said Potential Vacuum leaks would NOT cause high idle.....this goes against all that I though I had known, can anyone explain/verify this? 

anyone experienced any other reason i would get a high idle with the 4100???

as usual,
Many Thanks.  Jeff
 

 

11/27/2018 6:10 AM  #2


Re: Autolite 4100 "ECD" installed on 289 Coupe.........Troubles

Hi , check choke idle and related screw and spring ,  also how works throttle linkage and dashpod . 
Try to force the throttle to close . if works maybe is only  to set correctly links and joint  . 
From my experience some air leaking from intake , raise the idle ...   it's happen to me and was easy to find after mechanic explain me how to do it .  with oil lubricant he follow the intake border and start the engine with low idle . the oil keep only a little time the air passage close  after that returns high . 
I feel you are very sure that your engine don't suck air from somwhere .  how did you check it ? 
After that i don't know anymore to help you .  bye !

 

11/27/2018 9:51 AM  #3


Re: Autolite 4100 "ECD" installed on 289 Coupe.........Troubles

Vacuum leaks won't cause a high idle; they'll cause a low idle.  The only way speed increases with a vacuum leak is if something combustible enters through the leak.  That's typically how you find them, by spraying carb cleaner, etc. and seeing if the idle races. 

Are the throttle blades all the way closed?  Try disconnecting the throttle linkage and see if the problem goes way.  Check the primary and secondary blades. 
 

 

11/27/2018 10:30 PM  #4


Re: Autolite 4100 "ECD" installed on 289 Coupe.........Troubles

Thanks guys.....

I have the secondary blades backed off entirely and front Main Idle screw is backed off all the way (no longer in use)....before assembling and bench testing I ensure blades shut entirely, then I set them.....obviously tweak on car!.....

Jets are 56P and 63Sec with a 6.5PV.......maybe primary Jetting is too High?  but that would confused me only cause those came off a 1.14 2bbl autolite.....this is strange!

     Thread Starter
 

11/28/2018 6:48 AM  #5


Re: Autolite 4100 "ECD" installed on 289 Coupe.........Troubles

Jet size won't cause a high idle.  A rich idle, but not high.  Think about how little idle speed screw position affects RPM.  You might get 50RPM from moving the screw a full turn one way or the other.  Something else seems to be off here. 

 

11/28/2018 9:55 AM  #6


Re: Autolite 4100 "ECD" installed on 289 Coupe.........Troubles

M1Mustang69 wrote:

Thanks guys.....

I have the secondary blades backed off entirely and front Main Idle screw is backed off all the way (no longer in use)....before assembling and bench testing I ensure blades shut entirely, then I set them.....obviously tweak on car!.....

Jets are 56P and 63Sec with a 6.5PV.......maybe primary Jetting is too High?  but that would confused me only cause those came off a 1.14 2bbl autolite.....this is strange!

Mine were 47 p  and 56 sec And was too rich  , Lean a little and changed the     corroded idle mix screw .
Please can you explain  "  front Main Idle screw is backed off all the way (no longer in use) . 
in the 4100 are the mix screws  2 pieces with springs ?   why  is no longer use?
thanks 
 

 

11/28/2018 11:41 PM  #7


Re: Autolite 4100 "ECD" installed on 289 Coupe.........Troubles

I can back off the IDLE screw and it will still idle high (not in use)........there are 2 mixture screws and they have springs......

on a holley, normally this is due to secondaries open too far or primaries not closing all the way, for this one, im a bit stumped

     Thread Starter
 

11/29/2018 5:29 PM  #8


Re: Autolite 4100 "ECD" installed on 289 Coupe.........Troubles

Did you take the butter fly plates out of the shaft and put them back in? If so the plates could be in the wrong position. Hold the carb up to a ight with the idle screwed all the way out and look through it you should not be able to see hardly any light through it. If so readjust the plates till they both close all the way.

 

11/29/2018 5:39 PM  #9


Re: Autolite 4100 "ECD" installed on 289 Coupe.........Troubles

HudginJ3 wrote:

Did you take the butter fly plates out of the shaft and put them back in? If so the plates could be in the wrong position. Hold the carb up to a ight with the idle screwed all the way out and look through it you should not be able to see hardly any light through it. If so readjust the plates till they both close all the way.

To go along with the above, also make sure the plates weren't inverted- there's a definite top and bottom.

We're probably not telling you anything you don't already know but hopefully helping you cover the bases, but if both the primary and secondary plates are all the way closed it shouldn't run at all, let alone idle that high. It's worth checking.

 

11/30/2018 10:54 PM  #10


Re: Autolite 4100 "ECD" installed on 289 Coupe.........Troubles

Thanks Hudg and Jon........

I did recheck both these things multiple of times.....I ensured the beveled edge (top and bottom) were installed correctly and 0 light enters when both are closed off!

there must be a Vac leak at the flange!  very peculiar.....now the intake is a Aftermarket Aluminum which came off a 80's 302, so perhaps the mount is slightly different?  going to try a widened walled spacer on Sun.....see if that rectifies everything...........

     Thread Starter
 

11/30/2018 11:27 PM  #11


Re: Autolite 4100 "ECD" installed on 289 Coupe.........Troubles

Autolites are notorious for not sealing with most aftermarket manifolds.

Looking forward to you seeing this thru, I have a few EDC 4100's but haven't had a chance to run one so I'm curious as to how she'll run after the final tune is sorted out.

 

12/01/2018 7:39 AM  #12


Re: Autolite 4100 "ECD" installed on 289 Coupe.........Troubles

You can go hunting for a vacuum leak with a can or carb cleaner.  Just start spraying it in suspect areas.  If you get a change in engine speed you've found the leak.  One place to check, especially on older carbs, is the throttle shafts.  If the holes are worn they often leak right there. 
 

 

12/01/2018 2:19 PM  #13


Re: Autolite 4100 "ECD" installed on 289 Coupe.........Troubles

TKOPerformance wrote:

You can go hunting for a vacuum leak with a can or carb cleaner.  Just start spraying it in suspect areas.  If you get a change in engine speed you've found the leak.  One place to check, especially on older carbs, is the throttle shafts.  If the holes are worn they often leak right there. 
 

The OP posted earlier that he pressed new shaft bushings in but it's good to check there anyway for sure.
He could turn the factory space upside down for a quick check if it indeed leaking around the base, but that's a temporary solution as the bores are tapered to slow the flow.

 

12/01/2018 3:19 PM  #14


Re: Autolite 4100 "ECD" installed on 289 Coupe.........Troubles

A lot of those shaft bushing deals have to be reamed to fit, or are universal, so I'm always suspect.  I never understood why they didn't use seals there.  Some carbs I've seen over the years do, but not very many. 

 

12/01/2018 11:33 PM  #15


Re: Autolite 4100 "ECD" installed on 289 Coupe.........Troubles

TKOPerformance wrote:

A lot of those shaft bushing deals have to be reamed to fit, or are universal, so I'm always suspect.  I never understood why they didn't use seals there.  Some carbs I've seen over the years do, but not very many. 

I completely agree. Daze is going to start including throttle shaft seals with each set of venturi sleeves though, right? 😁

 

12/02/2018 7:37 PM  #16


Re: Autolite 4100 "ECD" installed on 289 Coupe.........Troubles

http://i65.tinypic.com/257hpoz.jpg
Thanks again guys......For starters, did find VAC leak on the base -------- AGAIN........
John Richard nailed it on the head with these factory jerks making these great factory FORD/Holley Carbs but they DO NOT play well with anything AFTERMARKET......its idiotic!...

2 spacer plates later and Still same leak.....posting pictures from phone video----------No solution comes to Mind!!!!!! anyone know what to do?

uploading 2 photos showing Vac Leak (big gap is rear and smaller is front) and 1 photo showing new spacer (take note of how wide the walls are - chosen carefully to try and eliminate the vac leak)


http://i68.tinypic.com/v5gz2f.jpg

http://i64.tinypic.com/dgqxwm.jpg


 

     Thread Starter
 

12/02/2018 7:59 PM  #17


Re: Autolite 4100 "ECD" installed on 289 Coupe.........Troubles

http://i65.tinypic.com/257hpoz.jpg
Thanks again guys......For starters, did find VAC leak on the base -------- AGAIN........
John Richard nailed it on the head with these factory jerks making these great factory FORD/Holley Carbs but they DO NOT play well with anything AFTERMARKET......its idiotic!...

2 spacer plates later and Still same leak.....posting pictures from phone video----------No solution comes to Mind!!!!!! anyone know what to do?

uploading 2 photos showing Vac Leak (big gap is rear and smaller is front) and 1 photo showing new spacer (take note of how wide the walls are - chosen carefully to try and eliminate the vac leak)


http://i68.tinypic.com/v5gz2f.jpg

http://i64.tinypic.com/dgqxwm.jpg


 

     Thread Starter
 

12/02/2018 11:05 PM  #18


Re: Autolite 4100 "ECD" installed on 289 Coupe.........Troubles

You may have missed it but I suggested you could turn the factory space up side down to temporarily get you by, but the bores are tapered to help slow the A/F charge so the fuel doesn't drop out of suspension when it enters the plenum.

Weiand makes aftermarket dual plane manifolds that work with Autolite carburetors and that really is the best solution, otherwise you'll have to stack another spacer between the manifold and Ford spacer.

 

12/02/2018 11:09 PM  #19


Re: Autolite 4100 "ECD" installed on 289 Coupe.........Troubles

Something like a carburetor heat shield- sorry, no link.

 

12/03/2018 6:50 AM  #20


Re: Autolite 4100 "ECD" installed on 289 Coupe.........Troubles

Or make one out of like 1/8" thick aluminum.  I'm guessing hood clearance may be at a premium.

 

12/03/2018 10:31 PM  #21


Re: Autolite 4100 "ECD" installed on 289 Coupe.........Troubles

http://i65.tinypic.com/257hpoz.jpg
Thanks again guys......For starters, did find VAC leak on the base -------- AGAIN........
John Richard nailed it on the head with these factory jerks making these great factory FORD/Holley Carbs but they DO NOT play well with anything AFTERMARKET......its idiotic!...

2 spacer plates later and Still same leak.....posting pictures from phone video----------No solution comes to Mind!!!!!! anyone know what to do?

uploading 2 photos showing Vac Leak (big gap is rear and smaller is front) and 1 photo showing new spacer (take note of how wide the walls are - chosen carefully to try and eliminate the vac leak)


http://i68.tinypic.com/v5gz2f.jpg

http://i64.tinypic.com/dgqxwm.jpg


 

     Thread Starter
 

12/04/2018 9:48 AM  #22


Re: Autolite 4100 "ECD" installed on 289 Coupe.........Troubles

When I was running a 4100 and a edel performer manifold I filled the back side of the Ford spacer with chopped FRP and used a .080 aluminum spacer to seal the leak.
 Now, the Performer RPM Edelbrock has added material on the carb base and the 4100 does not leak in that area.


Good work ain't cheap, Cheap work ain't good!   “My tastes are simple: I am easily satisfied with the best"
 

12/04/2018 7:21 PM  #23


Re: Autolite 4100 "ECD" installed on 289 Coupe.........Troubles

Rudy, I was thinking of doing the exact same......In fact I had already ordered a Heat Shield by Mr.Gasket!

was hoping filling the Void wasn't necessary, is it still!??

     Thread Starter
 

12/05/2018 9:36 AM  #24


Re: Autolite 4100 "ECD" installed on 289 Coupe.........Troubles

M1Mustang69 wrote:

was hoping filling the Void wasn't necessary, is it still!??

Perhaps not, as long as you can be sure that the heat shield will seal properly.
 I  did not want to chance it and tear every thing apart again.


Good work ain't cheap, Cheap work ain't good!   “My tastes are simple: I am easily satisfied with the best"
 

12/05/2018 5:57 PM  #25


Re: Autolite 4100 "ECD" installed on 289 Coupe.........Troubles

That’s not a lot of area to in the picture. What’s stopping you from filling in that area of the base plate with something like JB weld?


John  -- 67 Mustang Coupe 390 5 speed
 

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