newly installed carb problems-black smoke

[mlaird]

put a newly rebuilt motorcraft 2150 on my 75 and it idled great in the driveway yesterday. Problem is now it takes forever to start and i have to give it a ton of gas to get it to turn over and then a bunch of black junk shoots out the exhaust. this happens every time i try to turn it on but once i get it running it drives fine(havent gone over 35 yet). any suggestions?

 

[1970mule]

does it have an electric choke?
if so that maybe the problem. you need to adjust that.

 

[mlaird]

i believe it does have an electric choke. once its hot it starts right up even when i turn it off but if its been off for 10-15 min its tought to start and i get the black smoke

 

[1970mule]

yeah, too me it sounds liek its a choke thing. it is starving out cause it is not correctly adjusted. you might want to first check and see if it is getting a full 12 volts to the choke, then if it is try to adjust, open the choke up a little you just need to loosen some screws on the side and you can turn it clocwise or counter clockwise.

 

[larryh]

If the choke adjustment dosen't work., look for a possible bad power valve. I had the same problem with a freshly rebuilt carb. It was the power valve leaking.

 

[robinsoncc]

Play with you timing a little to try and match the carb. Also sometimes that electric choke gets stuck, another thing is to check if you are getting voltage to the choke. I believe you have to wire it so it always has power when the key or ignition is turned on. Another thing could be that you have to adjust the carb just mark it and remember how many turns so you can always set it back to where it was if it doesn't work.