Need some help with my 4100.I can not get it idle lower then 1000 rpms,at this time the idle speed screw is not even in contact with the throtle shaft and the fast idle screwis also turned all the way out and it still will not go below about 1000 rpms.The carb must be pulling fuel from some where.The sec.butterflys are set to factory specs3/4 off closed.Why is this thing still running with the idle speed screw all the way out, it runs great,no bog off idle.i just rebuilt the carb with the motorcraft kit,just like i've done dozen of times before.

Your answer will be there.

Except for one more possible and that would be something not installed or put back together correctly.

Good Luck,

Bill White
White Automotive

I don't think my problum is a vacum leak,vacum is steady by my gauge,15-16 lbs and a steady reading,I know that the reading is a little low but I have a non stock cam.these engine doe's not run crappy.runs good

Bill,i put a rag over the secondaries and it stared to run rough and die.My thinking is that I,m pulling fuel at idle thru the secondaries,it should not be.Secondaries are set to spec,s 3/4 turn after the scerw hits the lever.Can I back off the adj.scerw?