There are only so many things that can cause this problem. Other than what we have discusses, some other possibilities are:
1. the oil dipstick seal may not be sealing correctly. This will cause the crankcase pressure to be off and it will push oil out through the valve breather and into the carburetor where it will be burnt.
2. Check the oil dipstick tube at the bottom also, there is usually a sea at the bottom as well as at the top. Same issues can occur.
3. If the engine is overspeeding, it will burn oil as well as give you a good chance of blowing the engine. Check the RPM's to make sure that they are not running more than 3400 to 3500 max.
4. There can be a pinhole in the block caused by poor castings. This will cause air to enter into the block and cause oil burning. These early Courage engines were not built very well and were built in China where they have much lower build standards.
5. Double check the head gasket and head.
6. Valve guides can be worn and cause oil to burn because it can be pushed through the guides.
7. The piston ring could be worn or broken causing this problem. Also an out of round cylinder can cause oil burning.
8. A burnt piston can cause this problem as well.
9. Any Gasket on the engine can be leaking .... allowing air to pass into the crankcase, causing a crankcase imbalance and push oil through the oil breather .
I hope that this can give you a few more things to check and I hope you find the REAL problem.