Quadrajet Problem Solving > Dialing in your rebuilt Quadrajet carburetor

Need Idle help-Newly rebuilt with cliffs parts

<< < (2/3) > >>

77cruiser:
Is the body to base gasket correct? I had one that had the wrong gasket & had similar symptoms.
How far did you turn the screws out? Did you open the idle mixture holes a bit?

wj3v:
Answers below in red.


--- Quote from: 77cruiser on August 19, 2018, 02:33:21 PM ---Is the body to base gasket correct?
As far as I can tell its correct. But if needed I will take it apart and take another look.
 I had one that had the wrong gasket & had similar symptoms.
How far did you turn the screws out?
Tried from fully closed to all the way out.
Did you open the idle mixture holes a bit?
No I did not

--- End quote ---

Cliff Ruggles:
It is wanting more idle fuel if it smooths out when you place your hand over the choke area or "tip-in" the choke flap to richen things up.

Open up the holes under the mixtures screws to .086-.089".

Turn the mixture screws out about 5-6 turns and work from there.

What LSA is the cam ground on and where is the ICL set at?  That's a small cam in a 454 build and pretty low compression for aluminum heads.  It may simply want more idle fuel to be happy........Cliff

wj3v:
Cam spec:
Cam # 24502611   454HO roller cam
@   0.050
ID   211
ED   230
LSA   112
ICL   108

IVO   -2.5   BTDC (- indicates ATDC)
IVC   33.5   ABDC
EVO   51   BBDC
EVC   -1   ATDC (- indicates BTDC)
ECL   116
Overlap -3.5

I'll try opening up the mixture screw holes and see what happens. Probably won't be able to work on it until the weekend.

wj3v:
Had a chance to work on this tonight.
 I opened up the mixture screws to .092  They were .059.
Also opened up the the idle down channel to .058

Really improved the idle quality. Now has steady vacuum of 16" at 800 rpm. Can turn idle screw all the way out and still idles at 450 rpm.

Still have a few questions. I can screw the mixture screws all the way in and it still will run. They do have a slight effect but even with the throttle blades closed I would think it would stall out but it doesn't.

Also, if I remove a vacuum line the idle will speed up now. Maybe this is normal?

I also think I may need to put bushings in the base plate for the throttle shaft. I sprayed some carb cleaner there and it definitely made the idle even smoother.

Making progress on this has been very encouraging. I was amazed at the difference it made just opening up the idle circuits.  :D

Navigation

[0] Message Index

[#] Next page

[*] Previous page