All of Paul's advice/suggested are excellent.
Here is a way to test/observe:
- Disconnect the bell-crank to pedal linkage.
- The throttle return spring should still be connected (pulling the throttle downwards/"closed").
- Adjust the carburetor.
- Flick/turn the throttle quickly to a fast idle and release - does it return to idle?
- Turn the throttle slowly to a fast ide and release - does it return to idle?
