Acceleration decline after carburetor replacement

[iceicebaby]

Hello everyone, I just replaced a cracked and leaky carburator on my 73 Convertible 351c 2v (2 barrel) and the pedal and acceleration is very sluggish and bottoming out without shifting gears properly. The new carburator is not exactly the same as the last one I replaced some hoses because of length. So I am thinking maybe the throttle cable length is also compromised. The throttle cable does not have any screws to tighten it like others I've seen on youtube. I replaced some of the springs and it helped a little. any ideas or tips on how to tighten this throttle cable and or get my acceleration back?
thabk you for any input

 

[giantpune]

Did you get the vacuum line back to the transmission connected correctly? Without that vacuum line, the transmission wont shift up through the gears.

Another cause is if you dont have the throttle and kickdown adjusted correctly. If your setup is pulling on the kickdown lever too early in the throttle's travel, the transmission may not shift like you expect it to.

 

[Sheriff41]

Like @giantpune says, check for vacuum leaks (even at the vacuum module on the transmission) and make sure your accelerator pump is adjusted to squirt as soon as the throttle opens.

 

[piper62j]

The 2100 series carburetors are all basically the same from Ford.. You did not specify whether yours is an original rebuilt, or one of the cheap Chinese knock offs.. From what you stated, the throttle bore may be too small and the jet size is incorrect.. We need more information on what carburetor you got..

 

[basstrix]

If it hasn't been mentioned already, check the kickdown adjustment. That screw looks like it's all the way threaded in. Manually open the throttle, note how far it opens, then disconnect the kickdown and repeat. The kickdown should not impede the full rotation of throttle shaft.

 

[mrgmhale]

If the performance issue began upon installing the replacement carburetor it is likely a linkage related issue. That could be the throttle cable is not opening the carb throttle blades full when the accelerator pedal is pressed to the floor. Or, it is possible the kick-down linkage is missing, disconnected, or out of adjustment. That is easy to check, if you have a 2nd person to help you. With the pedal pressed to the floor look down the carburetor (Engine not running!) and see if the throttle blades are both fully opened and totally vertical. I have seen where at times the cable is hitting resistance at the forward end of its cable sheath, and the throttle was not fully open when the accelerator pedal travel had come to a stop. In some other cases the throttle cable mounting bracket had to be bent back a little bit to allow the throttle to open fully.

Another issue has been addressed already, above, where the kick-down linkage is not adjusted. I have seen kick-down rods disconnected, or missing outright. If the engine performance is flat after manually shifting into a lower gear when accelerating at Wide Open Throttle it is not likely the problem is a kick-down linkage adjustment. It is worth checking, however. I have attached a snippet from the 1973 Ford Shop Manual that shows how to adjust the kick-down linkage.

I hope that helps. If your issue persists after checking the info provided throughout this thread I am certain I am not the only person who would like to know.