Mr Smith et al,
I have run across a lot of these type stuck jets from some over zealous dude overtightening the jet(s). Whenever I can't get the impact tool approach to work, I just drill the jet and use an appropriate sized (#2 or #3) ezy out tool. That method has always worked and I always run a tap through the threads afterwards. Of course it ruins the jet, but new jets are cheap compared to losing a carb casting through hammer and tong approaches.
Jets shouldn't be tightened to much more than about 40 inch-pounds anyway.
Hope that helps solve the problem for you. Good luck.
Regards,
HB2
