carburetor adjustment

[DutchEdwin]

I have a Carter WCFB 4 barrel carburetor, type 2253S.

I read the manual on how to set the idle mixture, but unfortunately.....it only mentions the 6 cylinder engine.

Here is my problem.

The carb has 4 chambers. 2 primary and 2 for secondary, fast driving, extra power.

For this is a dual carburetor, I need to set two mixture screws.

I planned to set the mixture screws by measuring max vacuum (18-21 inch).

I did connect a vacuum meter in the intake manifold. There is only one hole in the intake manifold, going to cylinder #1, #2, #4, #7. (see first picture at the arrow). So I can meter 1 mixture screw. The other one goes to the manifold channels where there is no hole to attach.

However, I did see at the bottom of the carb, there are two cross way's that connect the carburetor channels with each other, just underneath the butterflies to the manifold (see arrow in picture 2).

Setting idle speed at 450 to 500 rpm, TDC at 4 degrees advance.

Question:

How do you set this carburetor or the right mixture.

Is the cross way between the left and right side of the two channels enough I can reed the vacuum at only one point.

Thanks, Edwin.

[Niel Hoback]

I can only try to tell you how I do it. Warmed up, running at idle with both mixture screws out 1 1/2 to 2 turns, Turn one screw out a turn or more to make sure its running rich enough and then turn it in until you hear and feel the slightest drop in rpm's. Turn it back out until you get the rpm's back, and then do the same with the other screw. Go back and recheck the first one to make sure you can't gain any more rpm's by making it richer. If you use a tach, it may be easier.

Drive it. Feel for hesitation on light throttle take-off. If so, back each screw out 1/4 turn and try again. Repeat if needed.

It's much easier for me to do it than to explain it.

Hope this helps.