1900 Rpms at idle (Way to high)

[acarlotto]

Any help! Here is what is happening.

Crank her up and it idles at about 1900rpms (Way to high). Put her in drive steady at 1000rpms. It is a Holley 600 double pumper with no choke and edlebrock pro intake manifold.

- I turned idle screw to lower- No change
- I messed with mix screws- nothing results
- Carb is clean and checked float levels
- Does not have any leaks that I can tell. Changed intake gasket a few months ago.
- unhooked throttle cable--nothing

Any Ideas;? Could it be caused by bad timing? Or just somethng in the carb? I am learning slowly but am still very new to this whole Mechanical inclined stuff so sorry if i do not make tons of sense.

THanks for all the help in advance as always you guys are always helpful .

 

[bax]

Check for a big vacuum leak. Like PCV valve, or base plate gasket

 

[Broncobowsher]

Check the throttle blades/linkage. They have to be hung up on something. Turning the idle screw shows that. If idle doesn't change by turning the screw, the screw isn't touching.

Timing cannot get you the results you have. You have something with the carb.

 

[TN1776]

My thoughts are there's a problem with the choke. I am not too familiar with Holley carbs but I know on my Qjet when the choke is engaged there's a fast idle cam that gets set. Once the choke opens a pall drops out of the way, the idle drops down, and the secondaries will open when given enough throttle.

Might it be something like that?

 

[NJB71]

ditto....I have a holley 650cfm avenger, the cam on the choke would stay open cause my electric choke wasnt drawing 12v source, I know u said no choke, but does mean that yours isnt wired???

 

[av bronco]

With the engine off look down the carb and see if the throttle plates are closed, if not you got something hainging up at the throttle linkage or choke linkage, if there closed you got a bad vacuum lesk.

 

[broncnaz]

He has no choke.
I'll second the vacuum leak some where. Other issues can be dirt or varnish buildup in the throttle shafts causing them to stick hosing it down with carb cleaner may help. Also check your throttle return spring make sure its tight enough and strong enough to pull the throttle closed. Check your linkage from the pedal to the carb for proper adjustment body mounts could sag and cause it to tighten up.
In short double pumper carbs are not the best idea for a bronco unless your racing it. They can be made to work but there are not ideal.

 

[Broncobowsher]

My first thought was choke as well. But I read

It is a Holley 600 double pumper with no choke...

So I didn't go there.

But if it had a choke and it is now gone. The remains of the choke fast idle could easily be the cause.