Carter Thermquade

[LJ-TJ]

So there are 4 adjustment screws on the Carter Thermoquade. Two on the front and two on the side.Problem is when the 440 is cold it will idle at the proper 700 to 800 RPM. Once it's hot the idle steadily drops until it stalls. Once after the first stall it continues to stall. Which of the four screws do I turn and in which direction do I turn them to increase the idle. The manual makes no cents to me.Thanks

[Elandan2]

The two screws on the right side are the idle adjustment screws. The bottom one is the fast idle screw. It contacts the throttle plate cam when the choke is closed and is fully released when the choke is open. This should be set for around 1700 RPM when the choke is closed. the screw above the fast idle screw is the idle adjustment screw. This one comes into play after the choke is fully open and should be set for about 700-800 RPM. The screws on the front are the idle mixture screws and usually don't need adjustment. If they are out of adjustment, refer to the service manual to readjust.

[DaveVA78Chieftain]

Dave's Carter Thermoquad Ref Page

[Eyez Open]

Dave's Carter Thermoquad Ref Page

Volumes of necessary info on that page. Below is a video of assembly, note the linkage assembly, most older carb linkages  are not setup correctly..yrs of tinkering.

https://youtu.be/HOFr3KRW_MQ

[LJ-TJ]

Ok so we've established I'm a neophyte. And we've established the adjustment screw is one of the two on the side of the drivers side of the carb. One looks like a tube the other looks like a regular carb adjustment screw. Which one do I turn to increase the RPM once the engine is hot and starting to drop RPM's and which direction do I turn it. I tried to tell you I ain't the sharpest knife in the drawer.

[RockwoodMike]

I'm a neophyte

I am not trying to be mean here, but you need to sit back and watch those videos that Dave posted before you start turning screws..

There are other things that can cause a hot stall..fuel delivery is one of them..If the fuel filter is plugged to where it get a small portion of the fuel it needs, it just simply can't run because it runs out of gas in the fuel bowls..

[RockwoodMike]

https://www.youtube.com/watch?v=_lJ5AzseOSI

https://youtu.be/sv8ggASU1jE?t=470

[LJ-TJ]

No offense taken. There's dumb and then there's the T.J. I sat through both the video's twice today. They might as well have been speaking French. Didn't understand a thing they said. Pissed me off on the one with the real carb and as when he got to the end and in the last few seconds pointed to the two screws I wanted to know about and nothing about them and the video ended. All I want to know is which of the two screws on the side of the carb do I turn to increase the idle when the engine is hot The one with the barrel or the one that's just the screw and do I turn it clockwise or counter clockwise. I have no intention of bending anything or unscrewing anything. I guess I'll just have to live with it the way it is. Put it in neutral keep my foot on the brake bring the idle up to 800 rpm and when the light turns green drop it into drive and away we go. 

[RockwoodMike]

I grew up in the 70s and I should have remembered this..Your idle adjustment screw is on the other side of the carb..

Take a look at these pictures...It is adjusted when the ignition is on and that big black solenoid is active and pushing out a center rod about1/4 inch..It hits the adjusting screw and that is how the curb(slow) idle is adjusted..turn the screw clockwise to increase the idle..key must be on..

Now if all of a sudden you lost your idle that solenoid may have quit working..

What that solenoid did back in the day was to keep your engine from dieseling when you shut the key off..

When you shut the key off, the solenoid let that center rod withdraw back into it and cause the idle adjustment to fully close the throttle plates..stopping the dieseling..

That barrel shape screw on the other side is the fast idle screw adjustment..it adjusts the high cold idle when the choke plate is closed on a cold morning..screwing it in clockwise will increase the speed ..

[Elandan2]

I don't think that TJ's carb has an anti-dieseling solenoid. His idle adjustments are both on the side of the carb. The weighted screw is the fast idle and the screw above it is the "warm" idle screw.

[RockwoodMike]

I don't think that TJ's carb has an anti-dieseling solenoid.

You are right..I didn't notice that..At least he knows what screw is what ..hopefully he can get it idling again

[DaveVA78Chieftain]

The two screws you are talking about are:

Curb idle screw (upper one) - baseline idle speed adjustment with engine hot

Fast Idle Screw (lower barrel shaped screw) - used to vary engine speed while engine warms up.

I fixed the link to the 1972 Thermo-quad Carburetor  Service Manual which has a  very detailed description of all this.

Curb idle screw adjustment is shown and described on pdf page 13 of that document.

Fast Idle Screw is shown on pdf page 12 (fig 27) and described on pdf page 13.

However, I do recommend you read through all these adjustment pages to ensure you get everything set properly.

[LJ-TJ]

>GRIN< Hehehe I love you guys. Thanks a million for putting up with this. I really do appreciate your time. I'll look up read up the information you suggested. Thanks again.We'll have to have a get together so I can buy the beer.

[Eyez Open]

Carbs we're and are complicated even when your familiar with them. That video I posted was there so one can see how the linkages work...and all the parts that are attached to the carb. As I've said before most old carbs have been tinkered to death.

As many have pointed out there is a cold high idle circuit and a warm idle circuit it would seem your warm idle circuit is not setup.

Those circuits are problematic...have been since first implemented..The rebuild video does show how all the linkages going together and the associated parts...Those thermos quads are a different animal yet they used a heat spacer for thermal efficiency..way ahead of the times and quite novel.