Adjustments from AFR readings of 11's at cruising speed.

[Chlngrcrzy]

I have my idle reading at 13.8 on the AFR. Cruising around i have had a steady 11.7"s and sometime in to the 12's without a load on the motor.(around 2000 to 2500 rpm) When i stomp on it it drops to the high 10's. As soon as i get the engine cooled down, i will pull a couple of plugs. Other wise, what should i be doing next? smaller primaries and even smaller secondaries? The AFR reads a percentage of oxygen, right? So in order to be in the in the 13's and 14's i would need to lean it some? Is the 13's and 14's where i need to be?

[cudabob496]

yes, your primaries and secondaries appear too large.
What engine, what carb, and what are your primaries and secondaries now?

[Chlngrcrzy]

I will have to tear down and check the sizes that are in their now. It is a 440, 4 speed manual with a Holley 750. I am at about 600-700 feet elevation if that matters.

[Strawdawg]

First, be sure your power valves are a couple of inches of vacuum below the cruise vacuum so they are not providing fuel under cruise vacuum and be sure they are not blown out.  Then, if the AF is still way low, then take the primary jets down four sizes and try it again.

[734406pk]

I have my idle reading at 13.8 on the AFR. Cruising around i have had a steady 11.7"s and sometime in to the 12's without a load on the motor.(around 2000 to 2500 rpm) When i stomp on it it drops to the high 10's. As soon as i get the engine cooled down, i will pull a couple of plugs. Other wise, what should i be doing next? smaller primaries and even smaller secondaries? The AFR reads a percentage of oxygen, right? So in order to be in the in the 13's and 14's i would need to lean it some? Is the 13's and 14's where i need to be?

My advice is: the carb tuning is the last step in the process. First, clean spark plugs, then set the base timing, and then the total advance. (clean air filter ) Adjust the float level, then idle mixture. Check your idle vacuum in drive, then calculate your power valve starting point. From there you can adjust your primary jet size. The carb tuning is done one step at a time, but a wide band O2 gauge is very helpful and will speed up the process. Kudos!