RE: Antique Engine
Try calling Fox and see if they can send you a copy of the instructions that go with the carb on your engine. One other thing to consider with your engine is break-in. If your engine has a lapped iron piston, it will take a very long and rich break-in period before it's ready for flight. If the engine hasn't been through this, it would anser the question of why it doesn't run right.
John