If you have a rear induction
drum valve engine made by us it will only run CCW. None were ever
made to run CW.
Due to the radical timing it will sometimes start and run CW at
low RPM's but when the throttle is opened it will either die or
reverse rotation on its own.
This is true with any
higher performance front or rear induction engine.
Note: Any reed valve
(like a Cox Baby Bee) or sub-piston port engine will run either
If you have a disk valve check this link Disk