I have a Ryobi 31cc single ring that I cannot get to tune out.

When I advance above half throttle it dies.
I had this problem on a Zenoah G-23. Turned out I was trying to use a too-large prop. When the engine hits it's mazimum torque to turn the prop, the RPMs won't go any higher.

This is with a Walbro carb
The carb could be messed up. These little things are fairly complex, and great care needs to be taken if you disassemble one. The butterfly orientation is very impoortant, as are the filter screens and jets. They are very sensivite to dirt and dust. Your workplace must be absolutely clean.

My fuel tank is a basic nitro setup with the pressure line venting to the atmosphere, could this be the problem, is this right??
Basic nittro? Are you running gasoline or glow fuel in it? The vent should be open to the atmosphere, and the klunk should be no closer than 3/8" to the back wall of the tank.

Dr.1