My weedeater starts fine, but the minute I touch a weed it dies! Like there's not enough RPM's ? Is there a way I can REV it up some?

Does the engine run at a high rpm without being in contact with a weed?

does the engine run at a high rpm without being in contact with a weed?
Actually, it doesn't seem to be quite as high as it should be.

Could be just the carb needing adjusted. Or could be that the throttle cable is hanging.

could be just the carb needing adjusted. or could be that the throttle cable is hanging.
What can be adjusted, and how do I do it?