I have a problem tuning my OS CVR 15. It has good compression it runs and idles (however it is idled high) on my starter box however as soon as the tires touch the ground (under a load) it dies.
The clutch has been rebuilt and is free

If the engine dies as soon as the tires touch, then the clutch is engaged. If it was free, then the engine would not quit. The engine's turning at a too-high RPM so that the clutch is engaging. You'll have to work with the idle to get it lower so that the engine doesn't quit when you set the car on its wheels.