Honda clone small engine, horizontal shaft, high idle?

It is on a baja warrior mini bike. I bought this bike from a guy who tried to make it a bit faster but left me with a problem. When starting the bike you have to jump on it as soon as it fires up because it starts going with out any twist of the throttle. I already cleaned the carb and the jets and tried adjusting the idle at the idle screw on top of the carb. The linkage looks fine and returns to the position it should. Also the clutch is in working order. How do I lower the idle?

Go to the side with the starter cord, and you will see the throttle lever sticking out. You will also see the cable going to it. Unscrew the screw holding the throttle cable in place. Once you have it loose and the cable can move, give it a little more slack, tighten it back up, and start it. Adjust it until you have it where it does not catch the clutch. Keep in mind, when you unscrew the screw, the cable will fling back, so try to hold it in place.

I slacked the cable and still have the same high idle. Any ideas on what to do next?