I was just given a skyhawk 90......it starts and idles perfectly, ive been through the carb but I can't get it to rev past an idle......i have even tried to slowy raised the idle via the idle screw but just as the rpm starts to increase it immediatley dies......no small amount of playing with the throttle will keep it running....its like someone turns off the key......it will immediately restart but it won't rev past idle.....any ideas?

more carb work it sounds like