I rebuilt the 2150 two barrel motorcraft that was in better shape of the two that came with my truck but I'm still having weird issues with it.

I put a rebuilt 352 in it and I'm using a stock replacement mechanical pump with the filter on the bottom that's new, new lines, cleaned tank and lines running up to it.

I'm not running any choke right now so it is tied open securely until I get the manual choke cable put on, it can sit for a week go out pump it twice fires right up.

When you are either sitting or driving it runs very rich at idle (light black smoke) and has a bad hesitation when you step on it.

If you rev it a couple of times and clean it out it will run fine but once it idles very long it loads up again and driving at partial throttle it doesn't like to stay running when you stop unless you clean it out again.

I completely disassembled and rebuilt the carb with a new kit and tapped the vacuum hole on the side that went to the choke and plugged it with a pipe plug while it was apart. The only vacuum line I have is from the back of the carb originally to the choke hooked to the power valve port now.

Float is set according to the book I don't remember off hand what it was now, carb is bolted straight to the intake no spacer thick gasket and I've tried all the adjustment holes for the accelerator pump which is also new.


I'm lost on what else to try at this point? I also need a new housing for the accelerator pump one ear cracked on mine getting the old roll pin out, does anyone sell replacements I've not been able to find one searching yet!

 

What is your altitude where you live? Also what size jets are in it? If your carb is jetted for sea level (#57) and you are at 2000 ft your carb will be rich.

 

I'm at 1,100 feet (south central Kansas) never change much over 500 feet elevation the places I go.

I reinstalled the stock jets but didn't check the size on them, I will have to pull it apart and see.

Will Holley jets fit? They will be a lot easier to come up with.

 

Holley jets won't fit, wrong threads. Google Walker carburetor parts they have huge selection of Motorcraft carb parts including jets.

 

The first thing that comes to mind is a float problem, you said you fixed it but it sounds like the Carb is flooding a bit..

Try setting your float a bit lower if nothing else seems to help

 

I had some spare time before work today and was able to fix the problem, the float was actually to low and it didn't have enough fuel in the bowl but the idle air/fuel adjustment screws were out to far.

I reset the idle mixture at 2 turns out, reset the float to the specs in the rebuild kit with the engine idling and tweaked the accelerator pump adjustment until it was just right.

I'm very pleased with the results and have no stumble or sputter now, smooth idle and the smoke cleared up. Cold or hot she fires up instantly and I can't ask for more for what it is.