Passing along something postive that happened.I in rebuilding an f-40 tractor had trouble with carb float sticking up and down,which either cut the fuel flow off or flooded.I took it apart several times and read about every fix i could read and tried them ALL with no luck...float itself was good.Recently i saw kits for sale,that wasn't there before,that said for carter ut cast iron top carb only that would cure sticking needle and seat problems.I ordered and installed kit this week and so far no problem at all which really made me happy.Kit has a differant needle and seat that is differant to say the least but it gets the job done.Hope this helps somebody else