Q-jet choke flap closed too much too long

[Telecasterjoey]

As the title says my choke flap is shut too much for the engine to run properly.
Once warmed up the carb works great but as of right now, with the choke engaged i have to keep my foot on the gas or the truck will bog down and die. I searched the forum but couldn't come up with an answer other than to switch to manual choke.

How do I adjust my choke to not shut as much. If I hold the flap open 1/4" it will run nicely but with it shut all the way it wants to die.

Truck is an 86 gmc , 350 with Stock q-jet
Any help would be greatly apeciated!
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[Restrorob]

Sounds like your choke pull-off is in need of adjustment or is faulty (blown diaphragm), It's supposed to open the choke a little soon as the engine fires to prevent the issue your having.

[Telecasterjoey]

Can I fix it or get a replacement part?
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[Restrorob]

Yes, You can adjust or replace it. Do a search on Q-jet choke pull-offs and see what you can find, My lunch break is over now.....

[jhngardner367]

On the driver-side of the carb,just behind the throttle linkage,there is a number stamped(vertically),such as 17080122,that will help i.d.the model,type of q-jet.With that #,I can check the book,and tell you how to set the choke plate.Send me a pm,and if possible post a pic of the carb from the front,and passenger side(choke side).

[Telecasterjoey]

Ok thanks! I'll take some pics when I get home tonight.
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[jhngardner367]

OK,I'll be here!

[Telecasterjoey]

Here are some pics of the carb! So the choke slowly moves out but never seems to open up enough so the truck runs right until it finally pops off.
I thought the pic of the number would be more clear lol, I'll have to get it again in the morning!

[jhngardner367]

First,check for power at the choke wire,with ignition on.If no power,check the fuse,in the fuse block.When power is applied(12v),the choke coil heats up,and opens the choke as the engine warms up.You'll have to drill out the 3 rivets that hold the choke coil in place,and use some small screws to replace the rivets. With the engine cold,open the throttle slightly,and rotate the choke coil ,until it just closes.Tighten the screws,to keep the choke at this point.Next,sart the engine, and see if it opens the choke slightly(3/16"-1/4").If not,loosen the screws,and rotate the choke to get the right space.This should take care of it( If the choke coil has an index tab,that prevents it from turning,just file it off,so you can make the adjustments).

[Telecasterjoey]

Thanks man I'll try that tonight!
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[Restrorob]

The adjustment procedure jhngardner367 posted is for the primary choke stat setting, It should be turned until the butterfly closes completely with just a slight tension to keep the butterfly closed.

To adjust the 3/16 to 1/4" initial opening on start up is done on the choke pull-off;





Check this adjustment with the engine cold and choke butterfly closed, Take your finger and lightly push in on the choke pull-off. It should open the butterfly the amount jhngardner367 posted, If not adjust the screw in or out unit that spec is reached;



Now start the engine and look at the choke pull-off and make sure it pulled the choke open, If it doesn't pull in and open the choke the diaphragm inside is blown, Then a new pull-off is in order....

[jhngardner367]

I stand corrected...restorob is correct.The adjustment I gave you,will adjust the choke,on older series,WITHOUT the vpo!SORRY! Thanks for the catch,restorob!

[Restrorob]

Originally Posted by jhngardner367

Thanks for the catch,restorob!

Hey No problem, I likely wouldn't have chimed back in had pics not been posted....

[sox8145]

i dont mean jack the thread but where did u get that braket for ur throttle cable?

[Restrorob]

That appears to be the factory bracket for his truck/engine.....

[sox8145]

yeah thats what i thought ive been looking for one for my q-jet and havent had any luck

[jhngardner367]

If I'm not mistaken,they also used that type of bracket on some of the lat3-'70s to early '80s cars.That's where I got mine from. $10 at a salvage yard.