hi everyone I have a 31cc ryobi i'm not sure what is wrong with it but it will start and run for a while then all of a sudden it will die when you have some revs on it. I have replaced the spark pug, fuel line, had a mechanic look at it, I replaced the carby and still doin it could anyone help me with this please as it has been driving me insane

 

Your pulse port from the crankcase could be plugged/partially plugged. Or your fuel cap may not be venting which would affect the fuel supply to carburetor.

Was the carb new or a used one? If the latter the pump diaphragm may be stiff and not working effectively.

Or the ignition module may be weak and not able to put out a good spark at the higher revs.

Does it start back up on a couple of pulls or do you have to fight it a little?