I couldn't find any info on Carp Lake.

Lake Washington in King County has large carp.

You should be able to find them in the shallows around the lily pads at the Arboretum or Jaunita Bay.

Potholes Reservoir near Mose Lake in Grant County has huge carp. You can see them cruising the surface and jumping.

You might call WDF&W in Olympia and ask their warmwater biologist.