Does the tip size in your torch match the diameter of the new flux core wire? ie not .9mm tip with .8mm wire.
see, I am confused there as "normal" small dia fluxcore is 0.9, another gentleman posted about 0.8 fluxcore sometime back and I queried it, but it does indeed seem that it is available and weldequip sells it, and its SIF, and he does not sell rubbish.Yep, got some 0.8mm tips just for the SIF .8mm wire