Not only are the carb settings factory rich, but old fuel is gummed up in there.
On the bright side, if it was never tuned, it was never run hot and lean.
Above post is correct. Once it's been run through it's basic break-in tanks it will NOT run with factory settings. When the LSN is leaned, the idle must also be lowered. The HSN is for WOT running.
Do you have the manual?