keep in mind on the eddy the spring control the step up rate of enrichment. the lighter the spring the later the enrichment.. and by changing the rod from say a 73-47 to a 73-37. it would the same thing as going from say a 107 to 117.....but only under loads......it will have the no change on the cruise.....some stumbles can be fixed by going to a heavier or lighter spring. by just bringing more fuel in earlier or later, and not actually changing the amount of fuel. if you have say a 7" spring.....from 7 and above vacuum you will be running on the thicker part of the rod.....below the skinnier part.
Thank you for that info. I did plan to mess around with the rods and springs and see if I can get it better
that spring and rods are very similar to a power valve on a holley, but you can alert the amount on enrichment with the rod.....not just the when......which the spring does. a vacuum gauge helps in tuning this......a good baseline is roughly half you idle vacuum. then drive with gauge and see where you are as far load wise on the gauge and adjust the spring.........major changes can be made in just seconds with the rods and springs....... I always add fuel first when tuning......an overly rich condition does burn up parts
When I tuned the AFB on my '66 300, I had the air/fuel monitor on it. I could notice some hesitation and surging when the AF ratio got just a little lean.... 15.5 or so. Ideal mixture is 14.7, so it doesn't have to be extremely lean before you feel it.... a little off and you'll notice it. I had it dialed in nicely for the summer..... when I drove it in the winter, the cool air made it lean and the hesitation/surge was back! To cure the off-the line bog, try to increase your pump shot. Make sure your float level is right too.
Ok will do. I plan to put in 70x52 metering rods and try some springs and see what that does. It should lean it up a little and move the pump shot up one notch. And I set the floats to what edelbrock recommended
The problem with the AFB clones is the secondary air valves are controlled by a counter weight, so their is no way to adjust it. The Carter AVS carburetors at least allowed you to adjust the air valves via spring tension sort of like a Q-jet. The Q-jet uses air valve spring tension and the primary vacuum break to slow the air valve down so that it doesn't flop in and create that huge bog. You can't do that with the AFB, so I am not sure you can tune out the bog from a dig or low speed.
I ended up switching to 73x47 metering rods and I moved the accelerator pump to the farthest from the carb body spot and it’s running great. A little more fine tuning and it should be perfect. Thanks for all the help guys. Had my first car show of the year today and I took home the best 1960’s trophy. Doing a full restoration yourself and with the help of friends is a lot of work but it’s paying off now.
