ORIGINAL: LNEWQBAN

Then, it is a barrel that is not free to rotate and / or a faulty barrel-lever connection.

Here is the manual for your engine:

http://manuals.hobbico.com/osm/40-46-65la-manual.pdf

Check page #18 for proper location of the lever respect to the barrel.

Disconnect the linkage and move the barrel all the way back and forth.
Pay attention to any restriction, while you pull it and push it at the same time you rotate.

If needed, back up the retention screw for the barrel.
If it needs to stay out, fix it in position with some thread lock compund.

Clean the surfaces of the lever and barrel where they make contact, and screw both tight as indicated by JohnBuckner above.
If the connection is not solid to your touch, then we need to worry about that screw's thread.

Regards!