I took my Bronco for a drive today and the idle was high. When I was driving it was idling at 45mph. I got home and checked the speed and it was at 2500 RPM and the idle screw made no difference. The throttle arm did not seem to reach it and I could not find anything keeping it from going that far forward.

Also, the choke plate is very loose and turning it all the way up or back does not make that much of a difference in feel.

What do I need to look at?

 

Look at the other side of the carb(the pass side). I bet your choke is holding the throttle open, there is a fast idle feature for the choke. If it's flopping all around it may be activated. Look on the pass side of the carb and see if you can figure it out.

 

I could not find anything over there holding it open. The screw on the fast idle cam is dead center cam. I am not sure if it is supposed to be that way or not. If I manually move it the choke plate gets stiffer and I can force the arm to the fast idle screw, but it still doesn't rest on it on its own.

 

The fast idle screw should not be touching the cam. If you watch the cam and the screw, as you open the throttle on the other side, does the fast idle screw leave the cam? If it does, that is what is setting your idle speed right now.

 

The cam I am talking of is on the same side as the throttle (maybe I have miscalled the part). It is sort of a double cam looking piece.

I have been working on it and here is the situation:

I replaced the accelerator cable today because the other one had no coating and the cable was frayed. I hooked it up to where it just reached the **** when the idle was at 750 RPMs.

When I removed the accelerator cable and moved the screw off of the "cam" I got it to idle at 750 in P again.

I then moved the plate holding the accelerator cable where it was longer and I pushed it in until I could attach it. But when I did this I got the same problem I have been trying to fix for a while now, the gas pedal has about 1/2"-1" of play and it gets stuck at high RPM's until I tap the gas pedal hard and quick to get it to drop off that "cam".

I have been trying to fix the tapping problem for a while now because it brings my idle speed way up which makes it hard in stop and go driving especially with my brakes currently. I thought the accelerator cable would fix this, but apparently it is something on the carb.

 

Sorry, I haven't worked on these brand carbs very much. Here's a manual.

http://www.edelbrock.com/automotive/...ers-manual.pdf

If you look on page 22, item #47 is the fast idle cam and it's on the driver's side of the carb. If I were to guess, when you mash the throttle the air rushing through the carb is opening the choke door, and is releasing the cam and letting the throttle come back.

You are going to have to keep playing with this thing till you figure it out. I am still pretty sure it's a choke problem.

Look at page 21. Look at item #14. That is a lever that is hooked to the choke shaft, that pulls on #47 cam on the other page correct?

 

Let's see if these pictures work. They have the same item numbers.




1. Step-up piston cover screws (2)
2. Step-up piston cover plates (2)
3. Step-up pistons (2)
4. Step-up (metering) rods (2)
5. Step-up piston springs (2)
6. Step-up rod retainer springs (2)
7. Pin springs (small) (3)
8. Choke connector rod & lever*
9. Choke piston housing*
9a. Choke piston housing seal*
9b. Choke filter*
10. Mounting screws (3)
10a. Choke housing retainers (3)*
11. Thermostatic coil assembly*
12. Baffle plate*
13. Choke housing gasket*



14. Choke/cam connector rod
15. Pump connector rod
16. Airhorn attaching screw (1)
17. Airhorn attaching screws (8)
18. Airhorn assembly
19. Pump arm screw
20. Pump arm
21. Pump connector link
22. Fuel inlet fitting
23. Fuel Strainer Screens (2)
24. Fuel inlet fitting gasket
25. Float lever pins (2)
26. Float & lever assemblies (2)
27. Needle & seat assemblies (2)
28. Airhorn gasket

 

Here's the other one.




29. Pump plunger assembly
30. Pump plunger spring
31. Primary cluster screws (4)
32. Primary venturi boosters (2)
33. Venturi booster gaskets (2)
34. Pump jet housing screws (2)
35. Pump jet housing
36. Pump jet housing gasket
37. Pump discharge weight
38. Pump discharge ball
39. Secondary booster screws (4)
40. Secondary venturi boosters (2)



41. Venturi booster gaskets (2)
42. Air valve & weights
43. Primary metering jets (2)
44. Secondary metering jets (2)
45. Fuel bowl baffle plates (2)
46. Idle mixture screws & springs (2)
47. Fast idle cam
48. Idle speed screw
49. Body assembly
50. Ported vacuum port
51. Full-time vacuum port
52. PCV valve port

*Electric choke models 1406, 1409, 1410, &1411

 

Not sure what the sorry is for in your previous post when your the one helping me.

Yes, your correct. #8 goes from the choke to a rod that connects to the plate. The rod connects to the rod (#14) which connects to the cam (#47). #47 then has a screw that sits against it that when it is not touching it allows the throttle lever to move forward and rest against the idle adjustment screw.

 

If I under stand your 3rd post (#5) if you remove the throttle cable the idle will come down to normal?
If so then where it bolts in the bracket by the carb needs to be adjusted or the cable is the wrong one.
Did you look into why the old cable went bad? Could it be because of the bracket?
Also how many return springs are you using on the carb?
Dave ----

 

Yes, it goes back when I disconnect the throttle and tap the throttle quickly to unstick it from the cam.

I am using 1 return spring.

The bracket has been messed with by the PO. The throttle cable is not perfectly straight going to the carb. I also don't know why it is so long between the bracket and firewall, but I don't think it is causing any trouble.

The cable was definitely the root of my problem of not being able to get the RPMs down, but that still doesn't solve why it keeps sticking on the cam and why the accelerator cable has to be pressed in a little and the gas pedal loose to get the screw to unstick.


My old cable was zip tied to the brake vacuum line with no plastic covering on the cable. I think someone messed it up when they put this engine in.

 

I think you have a few things going on here.


You also running an after market intake manifold? If so that could be why the cable may not line up right with the carb.
I have a few intakes for AMC v8's and the cable does not line up right because of the way they are cast. Only fix is bend the stock bracket or make a new one that will line the cable up better.


Now the cable you sure you are using one for a v8 and not a 6? I would think the 6 would be longer?


Last is something with the carb. I don't know that make of carb to help out but if the idle still sticks with cable removed there is something going on with it.
Dave ----

 

I am running an Edelbrock performer intake with and adapter of some sort (flat triangle). I have been trying to bend it, but it still may need some tweaking. I assume it must be perfectly straight and fully extended?

I am running a v8 cable for a 302, but the firewall may be different seeing as how my truck was originally installed with a l6 according to the vin.

I will call Edelbrock. I may have gotten a lemon carb with this now and both my floats sinking the other day.

 

I don't think the fire wall would be different between a 6 & 8, only for AC and non-AC as I found out.
Dave ----

 

Do y'all see anything connected incorrectly?
You can see the screw in the fast idle cam in this pic. If I tap the throttle quickly it will unset and go between the two cams.