There's a slight chance that he carries yellow. You can either test the e locus, or you can breed him to a yellow, and see what comes out.
If he carries yellow, each pup has a 50/50 shot of being yellow.
And BTW, there is NOTHING wrong with black.
All Labs secretly want to be black. I can prove it.
If you take a yellow hunting, it will waller in the mud like a pig, trying to turn itself black.