The Ford Barn

Flathead Fever · 02-27-2026, 08:39 PM

Is there a way to “dial in” dual carbs using the A/F individually? Also, was cutouts to see if there was an “A/F app”, and sure if enough there is was, but the hardware/firmware is not cheap.

As soon as you adjust the one carb it makes the second one out of adjustment. They have to be adjusted together. It really is easy to do it once you've practiced a bit. Be gentle with the screws, do not run them down into the seats hard, just barely until they touch and then back them out evenly for starters.

You want to disconnect the linkage from the carbs but make sure each carb has a throttle return spring while you are doing this. You want to adjust the idle speed, both throttle plate barely opened up. As soon as you adjust one A/F mixture you've changed the reading on the other carb. So, then you need to adjust the second carb but then you have changed the adjustment on the fist. You just need to go back and forth and back and forth until the idle is correct and both the carbs are finally adjusted evenly, same number of turns out on the A/F mixture screws. Then you need to adjust the idle speed, how far the throttle plates are open on both carbs at idle, they need the same amount opening at idle, it won't be very much. You can use a uni-sync to balance the carbs. All this does is verify the throttle plate are set the same at idle. Then you might have to adjust the idle mixture screws "again". You just keep going back and forth until the idle speed is correct, the a/f mixture is correct, and both carbs Idle mixture screws are turned out the same amount. It sounds confusing but it shouldn't take more than a few minutes to get them all dialed. Then when you have the carbs set you need to hook the linkage back up to them, without moving the idle plates by adjusting the linkage. Then make sure the carbs open all the way up with the gas pedal floored. This is all just to get it running, you might need to take it apart and jet the carbs and do it all again.

There's not much on YouTube. Here is a VW video on a uni-sync. All this is for making sure both carbs are open the same amount at idle. They were popular on VW's and foreign cars but come in handy on flatheads with multiple carbs.

ttps://www.youtube.com/watch?v=FDm7EtmfOlM

02-27-2026, 08:39 PM	#8
Flathead Fever Senior Member Join Date: May 2010 Location: Yucaipa, CA Posts: 1,492	Re: 2x2 on 8BA flathead Is there a way to “dial in” dual carbs using the A/F individually? Also, was cutouts to see if there was an “A/F app”, and sure if enough there is was, but the hardware/firmware is not cheap. As soon as you adjust the one carb it makes the second one out of adjustment. They have to be adjusted together. It really is easy to do it once you've practiced a bit. Be gentle with the screws, do not run them down into the seats hard, just barely until they touch and then back them out evenly for starters. You want to disconnect the linkage from the carbs but make sure each carb has a throttle return spring while you are doing this. You want to adjust the idle speed, both throttle plate barely opened up. As soon as you adjust one A/F mixture you've changed the reading on the other carb. So, then you need to adjust the second carb but then you have changed the adjustment on the fist. You just need to go back and forth and back and forth until the idle is correct and both the carbs are finally adjusted evenly, same number of turns out on the A/F mixture screws. Then you need to adjust the idle speed, how far the throttle plates are open on both carbs at idle, they need the same amount opening at idle, it won't be very much. You can use a uni-sync to balance the carbs. All this does is verify the throttle plate are set the same at idle. Then you might have to adjust the idle mixture screws "again". You just keep going back and forth until the idle speed is correct, the a/f mixture is correct, and both carbs Idle mixture screws are turned out the same amount. It sounds confusing but it shouldn't take more than a few minutes to get them all dialed. Then when you have the carbs set you need to hook the linkage back up to them, without moving the idle plates by adjusting the linkage. Then make sure the carbs open all the way up with the gas pedal floored. This is all just to get it running, you might need to take it apart and jet the carbs and do it all again. There's not much on YouTube. Here is a VW video on a uni-sync. All this is for making sure both carbs are open the same amount at idle. They were popular on VW's and foreign cars but come in handy on flatheads with multiple carbs. ttps://www.youtube.com/watch?v=FDm7EtmfOlM Last edited by Flathead Fever; 02-27-2026 at 08:54 PM.