Is there any way to adjust the richness of these things without changing rods or jets?

In the center of the metering rod arm is a set screw. Turning this clockwise will raise the metering rods up out of the jets and richen the mixture.

Thanks!

x2 ...what TH said.

Now on the secondaires .. you do that with an air-door adjustment.

Quote:

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In the center of the metering rod arm is a set screw. Turning this clockwise will raise the metering rods up out of the jets and richen the mixture.

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That is only true for part throttle operation of the primaries.

For WOT use you can adjust how far open the secondary air valve opens (stamped steel flap sitting a couple inches above the secondary throttle plates) . You could almost think of it as a choke, farther opened results in leaner mixture.

Here are the proper(as described above)ways to adjust/fine tune all three circuits and the accelerator pump circuit with illustrations.
**Note that on all T.Q. carbs, you adjust the circuitry externally when the basic jetting parameters are set

This will take several pics and explanations, so read on!

The fist pic shows the red pointer at the top of the accelerator pump stem. Note the ruler to the lt. of the pump stem.

You can alter the accelerator pump stem height to give a quicker start to the accelerator pump shot VS the movement of the throttle. To do this, you have to remove the accelerator pump linkage from the throttle shaft end and pump arm lever. Then you bend the front crook on the linkage to a tighter bend to raise the stem height. This will give you a longer pump shot.

Bending the front linkage crook the opposite will lower the pump stem and make the pump shot duration shorter and will delay the pump shot VS the movement of the throttle lever.

Pic:

This pic will illustrate how to tune the cruise circuit.

The red pointer shows the metering rod tree piston assembly lightly bottomed in the top and a small blade screwdriver in the piston assembly top screw slot.

To correctly adjust the metering rod assembly, first lightly bottom the piston assembly with the fast idle cam off/choke open. Then back off the center adjuster slot counter-clockwise until the assembly stops dropping. The keeping the piston assembly bottomed, start turning the assembly clockwise and as soon as you feel the assembly start to move up, go 1.5 turns clockwise.

To richen the main(cruise)circuit, turn the piston screw clockwise but be sure you count exactly how much you turn it. It should take less than 2 full turns to see any change in performance. This will usually get rid of any road speed hot weather surging in most cases.

Pic:

This is how to richen or lean the 2ndaries. You will simply pry with a slot head screwdriver at the driver front corner of the 2ndary air door.

To richen the 2ndaries, pry the front driver side corner foreward. This will make the air door open less vertically. Two things will occur:
1)less air will enter the 2ndaries,
2)the 2ndary spray bars will get a stronger venturi effect from the air door dimples being farther from the spray bars. Both of these changes equals more fuel drawn through the 2ndaries.

Pic:

This last picture illustrates how to fine tune the lead or slack in the 2ndary air door. If you have ever adjusted the 2ndary air door tension spring and just cannot get the car to launch hard without a bog, this is why and NO factory manuals will explain this.

On engines with big cams and less than 16" vacuum, it will be necessary to have little or possibly no slack in the air door.

The red pointer shows the 2ndary air door stop when the air door is closed. This is where the air door slack is noted.

By slack, I mean how much the air door back edge will push down with the engine running(vacuum to the choke pull-off). You will want to push lightly on one of the air door dimples with the car idling in neutral. The air door will rear edge will either drop down say .100" to may be .300" or it may have tension and will not drop down at all.

So if you still have a bog after several attempts to adjust the air door spring tension(I would suggest you adjust the air door slack first before attempting to adjust air door spring tension)you will need to remove the choke pull-off linkage to make the air door slack adjustment and it may take several tries to get it right.

You will be bending the rear crook forward to take slack from the air door under vacuum and bending the rear crook to add air door slack.

This adjustment will do two things:
1)it will re-time the first movement of the air door VS the opening of the 2ndary butterflies. This will initially affect the 2ndary jetting and how quickly the fuel pulls from the spray bars when you stab the gas,
2)it will affect the 2ndary circuit cutting in VS the extra primary circuit at wot.

Pic of air door dimples and air door stop:

This pic below shows the 2ndary choke pull-off linkage rear crook:

The last circuit is the idle circuit and how to adjust it. At the front edge of the base plate, you will find the two idle mix screws.

Turning each clock-wise will lean the idle circuit and counter-clockwise will richen the circuit. It is best to do this with a vacuum gauge hooked to one of the constant vacuum ports. You will turn each idle mix screw until you get the highest or most steady reading on the vacuum gauge.

**You can also dial-in the metering rod assembly adjuster this way too**

It would be best to idle down the engine to the same rpms the engine would have in gear.

Now you have what you need to fine tune all circuits on your T.Q. for max performance and gas mileage and let me/or above guys know if you have questions about further tuning, David.

Great info. Thank you very much.