Sounds about right, the newer briggs motors dont idle very low at all, I would suggest pulling off the cowling and cleaning out all the dirt and dust out of the cooling fins on the block as the newer engines cook pretty easy.
You can adjust the idle revs by gently bending the tab on the small govenor springtoward the back of the mower bit by bit till it has an idle acceptable for you.
Cheers, Joe.
