Quadrajet linkage is binding up

[ColinOpseth]

Hey guys,
I have a Quadrajet on my '69. The linkage is binding up and sticking open. I'm thinking I may have installed the throttle linkage incorrectly. Does anyone have a high resolution image that shoes the orientation/order of the installed parts?

I made a video showing my problem. The truck is undrivable right now because the throttle sticks open. Kinda scary.

Download if you will. It's in .MOV format (Quicktime).

http://www.iroc-z.org/backup/IMG_0506.MOV

Thanks for the help,
Colin

[Gumby]

make sure its not your base gasket, when I put a new one on with a new carb, it was catching the back two making things stick open. Just had to trim a little.

(Course I then ditched the stock thick base gasket, [wasn't the thick plastic one, but the thick paper one,] I use a sandwich of 2 paper thin base gaskets and a thin steel shim.)

[ColinOpseth]

Wow, that was fast..!

I pulled the carburetor off the truck and removed the top off the carb to measure the float. I have been having trouble since I put it back together. It did bind off the truck but I wanted to install the carb on the engine to see if the problem was solved (it had been puking fuel out the top because the float was set incorrectly).

Now it's binding up. In the video I made, you can see it goes about 75% of the way and then binds up. At that point, the secondary linkage jumps forward. Something isn't right but I'm not sure what it is. I have been looking for a good picture or schematic so I can compare but haven't found one, unfortunately.

[Gumby]

that was the quick answer, while I send the link to my cell to download, PC internet is SLOOOOOOOOOOOW it gets 3-4kbs a sec, phone gets 150-200kbs

but phone won't download the mov file, grrr

[ColinOpseth]

Haha.. I think I'm spoiled with my Verizon FIOS. The 5 megabyte file uploaded to my website in three seconds.

[ColinOpseth]

I uploaded it to YouTube. I hope this helps.

Also, I think I have the spring on the wrong way. Don't shoot me for that. I bought the truck from my dad with that setup but I think the spring should go from the bracket that bolts on the carb to the linkage. I'll fix that in the morning.

Basically, you'll see in the video that the linkage binds up and then jumps forward when I pull backward on the throttle linkage. Then, it sticks open so I have to manually push the throttle closed. I don't have a tach on the truck but I'd presume that the engine rpm only drops to about 1,500 rpm or so, unless I manually move the linkage closed.

Quadrajet Carburetor - YouTube

[Gumby]

need Dave to pop in here.

HEI451
http://67-72chevytrucks.com/vboard/member.php?u=97643

[Coley]

Try this....loosen all (4) carb 'hold down' bolts by a few turns (do not remove) and try it again.
Sometimes overtightening of these bolts can lead to warping of the carb body and this can result in binding on the shafts or the butterflies catching.
Good luck...keep us posted.
Coley

[ColinOpseth]

Hey Coley,
Before I pulled the carb off the truck everything was pretty smooth. I took the top of the carb off to check the float and when I put it back together it was binding like this. If I remove the throttle linkage it doesn't bind at all so I'm pretty sure that I have the linkage installed incorrectly.

I'm going from memory here but here's the order I installed the linkage from carb outward.

I have the accelerator pump linkage first (it has a slot in it that goes directly over the throttle shaft. Then I have another piece of linkage that slides over a bushing with two different-sized ends. On the other size is a small piece with a curved arm on it. Then I have the largest piece that connects to my accelerator pedal.

It looks like the piece of linkage that's held in place by that bushing and the secondary linkage are binding. If you watch the video you will see that the secondary linkage moves like it should but then pops back toward idle. The problem is that the bind prevents the whole setup from going back to idle. Not good!

Do you have a Qjet on your engine? Would you mind taking a couple close-ups so I could compare? I'll be home in a few hours and will do the same.

Thanks!
Colin

[ColinOpseth]

I took a few pictures of my linkage up close. Can anyone see anything out of order?

Thanks again for the help,
Colin

[geezer#99]

Here's what I see wrong.
That bracket that the long secondary control arm is hooked to is in the wrong place. THat bracket is also reversed. The tab sticking out below where the accelerator arm attaches should be up on the other side. I found a pic for you of how it should look.
One other thing. In your video. Secondary air valve is wide open. Why?
The pic link.
http://www.arkansaspontiacs.org/tech...tle/index.html

[ColinOpseth]

geezer,
You hit the nail right on the head! I had that piece of linkage backwards. After messing around with this thing for the last week and a half...here it is.

It's straight (in primer) and has a few wiring issues but it's solid. Currently, it has 2.5" ECE drop spindles up front. Plans are for 20" or 22" wheels and a static drop somewhere in the area of 5"/6"-7".

[geezer#99]

JUst curious. Why was your secondary air valve wide open in your video?