Fuel coming out of a 777 jettison pipe during takeoff?!

[MD83 1]

HelloI was on a 777-200 recently, and I noticed something unusual. When the engines spooled-up for takeoff, I saw approximatley ten liters of fuel coming out of the jettison pipe, located on the left wing. Is this some kind of overflow mechanism?:)

[Cessnaflyer 56]

I think you might have seen either a vortex or the fuel was leaking out due to expansion when it heated up.

[bic 44]

Sounds like it.I had this happen leaving Cairo on a TWA 747 in the 80s. We taxied back and they said ya too much fuel was put on.

[MD83 1]

Thanks for the replies!