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Thermoquad air flap spring issue

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Saskatchewan
I have a 1976 Cordoba with a 4bbl 400. It has a remanufactured carter thermoquad. I was having issuses with the car bogging down on acceleration. I found a video on youtube that was about adjusting the air flap. I decided to try it. While i was adjusting it, i heard the spring make a little noise. I took the car for a drive and on the highway when i gave it gas it kinda stuttered. When i got back to town, it started to stall at intersections. I made it home and there was smoke(?) coming out of the carburetor. The air flap was wide open. I removed the outer ring and inner screw and there was no spring. I assume that noise i heard earlier was the spring breaking. It must have fallen into the carberator. My question is "now what?". Did i break the carb? It was also leaking gas from underneath on the driver side. I assume that i can find another spring and install it but i am afraid that the leaking gas suggests i did some damage. Any ideas and suggestions would be appreciated.
 
Find a new spring and cross your fingers. You should be all right. Follow the specs from the manual.
 
The spring fell in the fuel bowl. You didn’t beak anything. You’ll need to take the top air horn off and reinstall the spring.

When you adjust the door you cannot take it all the way loose. Just crack it enough to turn the screw in the middle.
 
I have a 1976 Cordoba with a 4bbl 400. It has a remanufactured carter thermoquad. I was having issuses with the car bogging down on acceleration. I found a video on youtube that was about adjusting the air flap. I decided to try it. While i was adjusting it, i heard the spring make a little noise. I took the car for a drive and on the highway when i gave it gas it kinda stuttered. When i got back to town, it started to stall at intersections. I made it home and there was smoke(?) coming out of the carburetor. The air flap was wide open. I removed the outer ring and inner screw and there was no spring. I assume that noise i heard earlier was the spring breaking. It must have fallen into the carberator. My question is "now what?". Did i break the carb? It was also leaking gas from underneath on the driver side. I assume that i can find another spring and install it but i am afraid that the leaking gas suggests i did some damage. Any ideas and suggestions would be appreciated.
Do you have a spare spring? If you need one, say so.
 
Remember the choke pull-off also helps control how fast the secondary air valve opens. If the pull-off is bad the valve could open to fast and cause a bog in the eng. The pull-off has a slight restriction in it's vacuum source so it will retract at a certain rate so the air valve wont open to fast. When you get a spring back in it and adjusted if it still bogs check the choke pull-off because it not only pulls the choke open some it also helps control the air valve opening rate. Good luck with it. Ron
 
The spring fell in the fuel bowl. You didn’t beak anything. You’ll need to take the top air horn off and reinstall the spring.

When you adjust the door you cannot take it all the way loose. Just crack it enough to turn the screw in the middle.


The spring is at least 1 1/8" long,even if it broke,it could not come off the shaft unless the retainer cap/ring was missing.And,you do not need to remove the air horn to install the spring.
 
Remember the choke pull-off also helps control how fast the secondary air valve opens. If the pull-off is bad the valve could open to fast and cause a bog in the eng. The pull-off has a slight restriction in it's vacuum source so it will retract at a certain rate so the air valve wont open to fast. When you get a spring back in it and adjusted if it still bogs check the choke pull-off because it not only pulls the choke open some it also helps control the air valve opening rate. Good luck with it. Ron
Ron,
NO...The choke pulloff diaphragm assembly and link DOES NOT effect air valve opening rate on an the AFB or AVS carb. The choke linkage will prevent the secondary butterfly valves on both AFB / AVS carbs (lock out link) ftom opening, unless the choke is wide open. HOWEVER, it does control the air valve opening rate on several models of GM's Quadrajet carb....depending on engine/vehicle/transmission...
BOB RENTON
 
I have a 1976 Cordoba with a 4bbl 400. It has a remanufactured carter thermoquad. I was having issuses with the car bogging down on acceleration. I found a video on youtube that was about adjusting the air flap. I decided to try it. While i was adjusting it, i heard the spring make a little noise. I took the car for a drive and on the highway when i gave it gas it kinda stuttered. When i got back to town, it started to stall at intersections. I made it home and there was smoke(?) coming out of the carburetor. The air flap was wide open. I removed the outer ring and inner screw and there was no spring. I assume that noise i heard earlier was the spring breaking. It must have fallen into the carberator. My question is "now what?". Did i break the carb? It was also leaking gas from underneath on the driver side. I assume that i can find another spring and install it but i am afraid that the leaking gas suggests i did some damage. Any ideas and suggestions would be appreciated.
Welcome to FBBO. I will have a spring. Where r u at? Kim
 
Ron,
NO...The choke pulloff diaphragm assembly and link DOES NOT effect air valve opening rate on an the AFB or AVS carb. The choke linkage will prevent the secondary butterfly valves on both AFB / AVS carbs (lock out link) ftom opening, unless the choke is wide open. HOWEVER, it does control the air valve opening rate on several models of GM's Quadrajet carb....depending on engine/vehicle/transmission...
BOB RENTON


No the choke pull-off controls the air valve on the Thermoquad as I said and on the Quadrajet. It does not control the air valve on the AVS or AFB as I did not say it did. All 4 barrel carbs have a secondary throttle plate lockout when the choke is on. The Ford Motorcraft 4 barrel has a small piston in the carb bowl in a cylinder in the fuel to control its air valve along with a spring of course. I only meant the thermoquad because I thought thats what we were talking about. Ron
 
No the choke pull-off controls the air valve on the Thermoquad as I said and on the Quadrajet. It does not control the air valve on the AVS or AFB as I did not say it did. All 4 barrel carbs have a secondary throttle plate lockout when the choke is on. The Ford Motorcraft 4 barrel has a small piston in the carb bowl in a cylinder in the fuel to control its air valve along with a spring of course. I only meant the thermoquad because I thought thats what we were talking about. Ron
Ron,
I guess i missed the comment re T-Quad. As for the first model of the Q-Jet, it too had a hydraulic dash pot controllong air valve opening rate. Like wise, the Motorcraft 4100 series also had a hydraulic dashpot controlling secondary "air valves" opening rate which were located above the butterfly valves but were below the secondary booster venturi. The T-Quad was an OK carb in concept but tuning components were difficult to obtain....if you got a "good one" great...otherwise it was replaced by a Holley Spreadbore dedign. Just my opinion of course.
BOB RENTON
 
I suspect after adjusting you didn't get it locked and it unwound. It helps to have the proper tool for thermoquad air valve adjustment. You can check that the spring is still in place by turning the center screw clockwise and see if the valve starts to close. If valve closes then set it per factory spec. If I recall you turn adjuster till valve just closes and then add another turn and set the lock ring/screw.
 
I made a tool similar to this one, just stick a screw driver in the center and it allows you adjust both screws.

2001-1.jpg
 
The spring is at least 1 1/8" long,even if it broke,it could not come off the shaft unless the retainer cap/ring was missing.And,you do not need to remove the air horn to install the spring.
We’re working on a Thermoquad. Spring isn’t even .750 long. The shaft does not pass the entire way through the entire air horn, or spring. The end of the shaft has a slot and the screw has a slot, nothing in between.
 
We’re working on a Thermoquad. Spring isn’t even .750 long. The shaft does not pass the entire way through the entire air horn, or spring. The end of the shaft has a slot and the screw has a slot, nothing in between.

Once the air valve is attached to the shaft,that determines the shaft location on the right side of the air horn.The spring is then put on the shaft with the 90* L shaped tang against the air valve plate.The other end of the spring has a "small" hook that goes into the retainer that also centers and supports the shaft.Once the retainer is installed and adjusted,there is "no" way for the spring to come off the shaft.Also,if the spring is short,it will never hook to the retainer and still be long enough to contact the air valve.The spring has to be long enough to completely cover the exposed portion of the shaft from the plate to the retainer. I've got loads of T/Q parts,I'll send you a picture of the spring and also the correct spring if you want.
 
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