Sticky idle

[Rio24]

Need some Help... The issue I'm having is idle hanging up around 1500.  It will lower to normal (900 rpm) if I blip throttle.  Getting tired of doing that in traffic. Middle carb is hanging , but only when engine is running. Carbs open and fully shut very smooth when engine off. Vacuum holding plates open?. Maybe it has to do with the balance tube on the cannon manifold. all carbs have been rebuilt.  I swapped carb position and problem stays in middle carb.  I heard the cannon manifold suck.  Does anyone have some helpful info for me?  TIA.

[Zed Head]

If you pull the pedal up with your toe does that solve it?  Fast idle means air is getting from somewhere.  B;ipping the throttle just lets the blades slam shut instead of sticking on a slow close.

[Duffman]

Same issue on my triples with Cannon intake; was getting stuck idle no matter what I did!  After some reading, and discussion with Mike at Pierce Manifolds, I am a believer that the 3 post/rod ends are causing binding that will not be easily resolved.   Essentially, it is very difficult to get all three "holes" to line up perfectly for the rod, thus causing a bind. 

I am going to try removing the center rod post (run on 2 rod ends, not 3), increase the rod and rod ends to 3/8" and see if the linkage will be much smoother.  Otherwise, will move on to another intake manifold, if necessary.

[Rio24]

@Zed Head  I have a cable set up, so pulling up on pedal does nothing for me .  I'll check again for air leaks. Thank you for your time

[Rio24]

Hey @duffman  I tried removing the center post last year and it did not help at all.  Good luck. I just order a external spring linkage though pierce manifold (Search DCOE external spring on google) hopefully that solves it. If not I'm buying a new manifold.   I 'll let you know.  

[wheee!]

15 minutes ago, Rio24 said:

@Zed Head  I have a cable set up, so pulling up on pedal does nothing for me .  I'll check again for air leaks. Thank you for your time

My cable setup will still close the butterfly when I pull up on the pedal...

 

Edit: NVM, I missed the cable to bar linkage issue.

Edited August 16, 2019 by wheee!

[Duffman]

Rio24, I have been told that the 5/16" rod that comes with the intake is not as good as the 3/8" stainless steel rod that Pierce Manifold sells.  You may have removed the center post, but still used the smaller (thinner) rod and that doesn't work as well, am told.

 

I am also getting sticking even with the cable linkage.

Edited August 16, 2019 by duffman

[Zed Head]

15 minutes ago, Rio24 said:

@Zed Head  I have a cable set up, so pulling up on pedal does nothing for me .  I'll check again for air leaks. Thank you for your time

That tells you that the binding is at the throttle linage on the manifold, not at the cable or the pedal.  You can extend the the thought process and push on the linkage with your finger.  Open the hood and poke around and you'll probably realize something.

Your picture shows that you have quite a bit of slack in your cable.  Seems like a good tune of the overall system might help.  Lots of adjustable bits there.

Edited August 16, 2019 by Zed Head
pole poke

[Rio24]

@duffman you have a good point!  Now should I try the beefer rod for 150 and hope that takes care of the issue or spend 500 on kenmeri manifold?!!  

[Duffman]

The total from Pierce Manifold for the 16" x 3/8" rod, 2 - 3/8" rod ends, adapters for the Cannon intake and 2 - 3/8" end links to hold the rod in place amount to about $80.  Pretty cheap alternative to a new intake (at least to start!)

Edited August 17, 2019 by duffman

[Zed Head]

No offense intended to the guys with the problem but buying a new manifold to fix a linkage problem makes little sense.  There are three throttle blades and linkage to make them work together.  If the blades aren't sticking it's the linkage.  If a new manifold works it's because it came with new linkage.

[Duffman]

That is why $80 to fix the linkage is a better option to begin with, Zed Head, I agree it doesn't make sense to throw big money at it, if you don't have to!

Edited August 17, 2019 by duffman