Certainly could be gummed up carbs but I would also look for air leaks on the intake side, particularly the vacume caps. Check that the aircleaner element is clean and clear.The carbs have started spitting back at low RPM's under load, and its getting progressively worse. I'm assuming a partly clogged pilot jet is to blame, but could there be other possibilities? The mixture screw is already 3 turns out.
Good pickup on the Procom ignitor there prop I missed that.Althogh if this only just started - try putting your stock ignition box back on and see if that helps.