I drive a 1981 Ford F-100 with the 4.9L inline 300. I have been having a problem with the carburetor when I start it when it is cold about 40 or so degrees and take off down the road, after a while it starts flooding out and the idle goes down and it puts out a lot of smoke. it only happens when it is cold and if i stop and turn it off and let it sit for a few minutes it runs fine. I asked a mechanic and he told me that the float valve needle had something in it. i took the carburetor apart and everything inside was clean. It started only about a year and a half ago and on chilly mornings it will do this it is very annoying.
thanks for any help i get