The Captain told the First Officer to declare an emergency, but the First Officer didn't use the word "emergency" in speaking to ATC so it's not surprising that ATC didn't recognise it.

Yes that is true. I remember that. Maybe the Captain should have told ATC that if they couldn't land at JFK soon then they would divert to KBOS ASAP.Daniel

If I can remember correctly there was still fuel in the tanks (still very little) but during some point they pitched up and that fuel couldn't reach the intake valves.