Was the fuel leaking out the bottom of the fuselage, or getting inside the wing(s) from the fuselage?
If it was leaking from the belly of the fuselage on take off, it would seem to me that with the throttles wide open, the heat to light the fuel should have been adequate before reaching rotation.
Tanks didn’t start leaking right away but shortly after T/O
No “fuel leaks”...center tank fuel vapor explosion caused by a spark. High voltage got into the the tank via the fuel quantity indication system wiring {normally low voltage}...insulation chafing caused a short to high voltage.
Page 308:
https://www.ntsb.gov/investigations/AccidentReports/Reports/AAR0003.pdf