Metering Rods and Jets Carter WCD

Adjusting the metering rods is a precision task. These rods control the air-fuel ratio by moving in and out of the main jets; if they aren't synced perfectly with the throttle position, you’ll end up with a "flat spot" during acceleration or a motor that runs far too lean at cruise.

Since you've already handled the pump adjustment, here is an expanded breakdown of the metering rod synchronization process:

1. Zeroing the Throttle Valves

Before touching the rods, you must ensure the throttle plates (butterflies) are completely closed.

• The Procedure: Back out the idle speed screw (throttle lever set screw) until it no longer touches the lever.

• The Goal: You want the valves to seat firmly against the carburetor bores. if they are even slightly cracked open, your "zero point" will be off, and the metering rods will lifted too high at idle.

• Tip: Tap the linkage lightly to ensure the springs have pulled the valves fully shut.

2. Setting the "Bottom" Position

The metering rods rely on the vacumeter link to move.

• The Procedure: Loosen the clamp screw (F) so the arm can move independently of the shaft. Press down on the vacumeter link (G) until you feel the metering rods "bottom out" inside the casting (H).

• Verification: You are feeling for the rods to hit the seat of the main jet. They should be at their absolute lowest point of travel.

3. Synchronizing the Arm and Link

This is the "handshake" between the throttle and the fuel circuit.

• The Procedure: While holding the rods in that bottomed-out position and keeping the throttle valves shut, rotate the metering rod arm.

• The Contact Point: You are looking for the "finger" on the arm to make light, precise contact with the lip of the vacumeter link (J).

• Tightening: Once that contact is made—without lifting the rods or opening the throttle—tighten the clamp screw (F).

4. Final Verification

After tightening, check the synchronization:

1. Open the throttle slightly and let it snap shut.

2. Ensure the rods seat fully at the exact moment the throttle hits the "closed" position.

3. Reset your idle: Don't forget to turn your throttle lever set screw back in to your base idle setting (usually 1 to 1.5 turns after contact) so the engine will actually start!