O.K. I've got a problem that I should be able to solve easily....but I'm scratchin' my head. The carb linkage on my '71 L-48 (I know, it's puny...I'm trying to make it less puny) has been adjusted to let the secondaries open all the way when I pull the cable back manually. BUT, when I push the accelerator pedal full-down, the secondaries are only open about 20%. The linkage needs to be adjusted somehow, but I'm not sure what is the best way to go about it. Do I bend the pedal rod to provide more pedal movement? Do I insert something on the accel cable to "tighten up" the slack in the system? Or is there a better way to make some adjustment?

 

Is this with the stock carb?.....

 

Nope thats pretty much it-If you have checked the mount on the carb-if it swings forward the carb wont open all the way-I shorten the cable by putting a zip tie around the cable inside the car between pedal lever and the little metal ferrel.Also make sure your pedal mount is not broken.

 

The pedal mount and cable appear to be fine. I don't know if the previous owner had a cable replaced (I can't believe it's been this way from the beginning). I'll insert something on the cable as you suggested and see if this works. If so, I'll replaced the temporary "fix" with something more permanent. Thanks for the reply.

 

I had to pull my cable housing back towards the firewall. tighten the clamp down then I put a tiny hose clamp behind the hold down to make sure it wouldnt slip forward when i mash the pedal down......... which isnt too frequent

Its got a hint of bubba but it works great

 

Just a follow-up for those that responded.... As always, I have learned a lot about the accelerator/cable system while thinking about this problem.

To take up the "slack" on the cable, I have added a 'clump' of two-part hard-as-steel epoxy right next to the crimped ferrule at the end of the cable. When that hardens, it should give me the right amount of pedal travel. If not, I'll add a bit more epoxy and try again. [I'm waiting for it to harden as I'm writing this.] Thanks to those who responded.

 

I put a band around it to act as a spacer to give me a bit more pull, take a look.

 

I bent the pedal rod on mine. The pedal rod is kinda light duty. I like VABEACHVETTE's clamp idea.

 

THAT'S WHAT I'M TALKIN' ABOUT!!!! Wow! That's what I expected for acceleration when I bought this "puppy" last summer. When I got it, it was very weak.... but no smoke or problem sounds in the engine. I did a full tune-up and rebuilt the carb; it ran fine, but it didn't perform very well. I'm embarrased to say that I never thought about seeing if the secondaries were fully opening.....until I read one of the Forum threads last week. Sure enough, too much slack in the accel. pedal/cable system.

My epoxy "clump" idea worked just fine. No slack in the pedal and the carb is now very responsive. Reminds me of the feel I got when I had a brand new '68 Chevelle SS396 with the 325hp motor [maybe a bit less].

I wasn't looking to give myself whiplash....but, at least, NOW IT FEELS LIKE A CORVETTE!

 

Looks identical to the method I used
Are you sure the inner return spring is not catching on the secondary linkage?
I had my return spring mounted on the inner hole of the throttle and it was binding on the secondary linkage.

 

VABeach I noticed that the accelerator cable on your car is hooked up to a different spot on the throttle shaft than the calbe on Bob Onits car. While I dont have my 71 at home right now to compare I think placement of the cable makes a difference.

 

The mount has swung forward in your picture---the hole around carb stud is probably elongated or the stud hole in carb base is worn out.

 

Ok since we're talking about a 71 here's my stock setup for reference...and the secondaries do open.

 

I probably have mine setup in the wrong hole
Look how far back my cable sits in the hold down.

Ill change it later as the ball does have a nut on the inside so it's easy to move it.

 

Bob,
My throttle cable mounting nut is in the same hole as yours. In fact, the stud won't even fit through the smaller hole below. And my cable body has to be placed farther back (compared to the AIM diagram) for it to work correctly. I assumed that the prior owner had the cable replaced, but now I'm not so sure. Anyway, this thing works like a charm now. It even validates that I did a pretty good job on the Q-jet rebuild.

 

Its funny you should say that yours is in the same hole as mine is...I do recall checking for WOT.
I had a friend hold the pedal to the floor and I was still able to get a little more out of the linkage by hand so I moved it to the upper hole because it seemed like the lower hole was actualluy "camming or rolling over" hard to explain but it was like once it hit 12:00 or so it stopped rotating. The cable actually started to slack out.
The only hole in my theroey is the fact that this could have been the case when I was running the Holley... so I really dont remember...... I will try the other hole (I have many mounting pins with a couple of different size threads. I believe the smallest is probably about 1/8" or so, and the largst about 1/4"
There should be a tiny bit of slack in the cable so its easily drivable.... too tight and there is no freeplay in the pedal which I believe is needed to take off without jerking the car all over, especially If its a standard shift.
Ill try the other hole and let you guys know how I make out...

By the way, I am missing the cable cover as mine is most likely the original and the plastic was brittle and cracked which was causing binding problems so I gently crushed what was left with a pair of pliers and it fell apart no problem.

 

Hello and good morning!
I Just took a look at my 1973 Chevrolet Service Manual and it shows the throttle cable installed in the upper hole on the Quadrajet.
I will still try mine in the lower hole so I have a comparison.
That is all.
Fall Out!

 

fyi...you can still buy these from GM for about 20 bucks. Mine looks like the one you describe and I thought I would purchase a spare just in case it ever frayed or broke.

 

I found a few in the 2 shoeboxes full of QJ parts I Picked up last month
I just diddnt realize they could be replaced....easily