Choke not closing on rebuilt quadrajet

[yellowdog5]

I believe GM, back in the day, had a drainage problem with some new cars, so they came up with a fuel filter with a flapper valve to prevent fuel from draining out of the carburetor.

I have bought filters with and without the check valve, the one I have now does have it. Going out now to try to adjust the choke.

 

[yellowdog5]

As Frankenchevy Suggested, I tried to adjust the choke turning the dial on the electric/thermostatic? choke. The choke is wide open and the adjuster does not move the choke. Am I correct in thinking it is either improperly installed (the "mechanic" replaced it), or else the spring is broken? Or is it linkage? He also replaced the choke pull off. The one I bought is like this one:https://www.rockauto.com/en/moreinfo.php?pk=39966&cc=1051805&jsn=551

 

[Backfoot100]

My guess would be improperly installed.
Take that black cover completely off the choke.
When you remove it you'll see a coiled wire spring with a hook formed on the end of it. That coiled wire is part of the choke linkage.
There should be a tab on the inside of the cover that needs to go into that hook on the wire. Its kinda tricky to get it right but you should be able to easily see what I'm talking about when you take that apart.
Once properly attached, rotating cover will open or close the choke. Then you can adjust it as described earlier.

 

[HotRodPC]

I believe GM, back in the day, had a drainage problem with some new cars, so they came up with a fuel filter with a flapper valve to prevent fuel from draining out of the carburetor.

Mine is both problems, the check valve in the fuel pump and the well plugs leak. When I let it sit for over 2 days, all the fuel has ran back to the tank and the carb bowls are empty. I call it my anti theft device. They gotta crank it for awhile and probably think it doesn't run and will give up.

 

[yellowdog5]

My guess would be improperly installed.
Take that black cover completely off the choke.
When you remove it you'll see a coiled wire spring with a hook formed on the end of it. That coiled wire is part of the choke linkage.
There should be a tab on the inside of the cover that needs to go into that hook on the wire. Its kinda tricky to get it right but you should be able to easily see what I'm talking about when you take that apart.
Once properly attached, rotating cover will open or close the choke. Then you can adjust it as described earlier.

Thanks

 

[Red Rex]

I ran a wire from the choke housing screw to the battery ground post. Once you get the linkage right be sure the carb is grounded good or the choke plate will take excessive time to open, creating a rich mixture issue

 

[yellowdog5]

Thank you guys so very much for being willing to help people. I got the spring attached to the linkage without too much trouble and was able to adjust the choke, not sure I knew what I was doing there as it was flooding really bad at first, but I played with it and got it running really well. It idles fast, I found a video I'm going to watch on tuning, we'll see how that goes. Now I need to see if it will start this morning, and I will check to see that the carb is grounded.

 

[Backfoot100]

Does it have the black puck looking doohickey with three screws holding it down?

If so, first thing in the morning a full press of your throttle pedal should set(close) the choke plate. If it doesn’t close try this: mark the black puck at 12 o’clock so you know where you started, loosen the three screws enough to rotate the black puck until the choke plate just barely closes. Don’t burry it forward; in fact, go till it closes then back off a smidge. Then retighten the screws.

Btw, you’ll need your air filter removed to see what you’re doing. Only do this while it’s cold.

This how you set the choke now that you know its properly installed.
Only can be done when cold before you turn the key on. Set it by a full pump of the throttle and then make sure its closed (or almost closed). I normally set it so its got about 1/16"-1/8" gap when closed.
Then you can start it. The choke should open up completely in about a minute then.

 

[yellowdog5]

I got it adjusted well enough to start cold, it still needs adjustment. I looked at some you tube videos on adjusting. On my carburetor I can't see the 2 screws in front, they are recessed way in, not like the photo in the best video (attached). I can't see them at all. I can get to the left one with a thin screwdriver, it feels really stiff, not sure it should be that way? I'm headed to the parts store to get a vacuum &pressure gauge and flexible adjusting tool, but if anyone has any pointers I can sure use them. The video says attach to where the pcv valve attaches to check vacuum, I wonder if the smaller port on the right would be just as good? It is plugged off on my carb. The instructions I watched that made sense were on you tube "How To Quadrajet Carburetor Rebuild - Part 3:" by Shop Tool Reviews

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[Frankenchevy]

I don't know exactly which carb you're working with, but the smaller port may be a ported vacuum source. When adjusting your carb and/or timing based on vacuum readings, you want to use manifold or 'full' vacuum such as the port going to your brake booster.

 

[yellowdog5]

Thanks everyone, I have it running nicely now, the only thing is that when it's cold I have to pump it 10 times before it will start. Can I fix this? I have adjusted the idle with a vacuum gauge. And idle speed is about 850 rpms

 

[75gmck25]

The mixture screws on a Quadrajet are hard to reach, but I can usually get to them with a small blade screw driver. Original screws had a double D shape (square on top, bowed out on both sides), so if a screwdriver works they have been replaced at some time. Due to emissions rules, the original design also included anti-tamper caps that had to be cut off to make the screws accessible. I think thats why they are so far back under the edge of the carburetor body.

If you want more info you might buy the Cliff Ruggles book on Quadrajets. It has lots of pictures, and info on all different versions of the Quadrajet. It can get confusing because some of the tweaks don't apply to all years of carburetor, but the information is really u

 

[yellowdog5]

The mixture screws on a Quadrajet are hard to reach, but I can usually get to them with a small blade screw driver. Original screws had a double D shape (square on top, bowed out on both sides), so if a screwdriver works they have been replaced at some time. Due to emissions rules, the original design also included anti-tamper caps that had to be cut off to make the screws accessible. I think thats why they are so far back under the edge of the carburetor body.

If you want more info you might buy the Cliff Ruggles book on Quadrajets. It has lots of pictures, and info on all different versions of the Quadrajet. It can get confusing because some of the tweaks don't apply to all years of carburetor, but the information is really u

The number of mine is 17059226, the type if I have it right is R4-M4MC. The mixture screws are actually hex, I did adjust them according to a video "How To Quadrajet Carburetor Rebuild - Part 3:" by Shop Tool Reviews, he said that some people use the brake booster port but he liked the one where the pcv valve connects to the carb, do you think that's OK? I turned the screws all the way in, backed them out 2 1/2 turns, then adjusted to maximum vacuum, which ended up about 16. There was very little variation in the vacuum about a pound or less, is that normal?
The truck takes 10 pumps to start it cold, but once it has been warmed up it starts easily. I'll try to find a used copy of the book if I can.

 

[yellowdog5]

Starting a new thread on my current problem, i hope that's OK.

 

[Snoots]

You've got a leaking well plug(s) and the internal pump is trash. You need to replace the internal pump with one that has seals that can handle these ethanol infused fuels. Seal the wells while you're in there.