LIL WAYNE Runs Up $868k Tab WITH UNCLE SAM

Lil Wayne's got more lien problems ... this time it involves his 2014 tax bill.

Uncle Sam says he did not pay $868,000 in federal taxes that year, according to docs. 

It's a ton of dough, to most of us, but as tax liens go ... Weezy's seen bigger. He waspreviously hit with a $12 million lien for several years of unpaid taxes.

Wayne was in arrears as of mid-January. It's possible he's already paid it off. We reached out to his camp, but no word back yet. 

The Jasmine Brand first reported Wayne's new lien.