Hi Michael,
Bubbles in fuel line are nothing to worry about- don't be scared to have a go at the carburettor as they are a pretty simple device.
One other thing to check is that the carburettor top cover gasket is the correct way up- it is possible to put it in upside down which can block some passages and expose others that should be sealed. There is a locating pin that makes it easy to work out.
Good luck!
Bubbles in fuel line are nothing to worry about- don't be scared to have a go at the carburettor as they are a pretty simple device.
One other thing to check is that the carburettor top cover gasket is the correct way up- it is possible to put it in upside down which can block some passages and expose others that should be sealed. There is a locating pin that makes it easy to work out.
Good luck!