Typhlosion- Burn Up, or Fire Blast?

[PkmnTrainerV]

I've been using Typhlosion with- Eruption, Earthquake, Fire Blast and Focus Blast.
Should I replace Fire Blast with burn up to make it a normal type against waters? Or shouldn't I change this at all?

Also, any improvements to this set would be welcome.

 

[UB-01 Kenobi]

Since Typhlosion should just about always be packing Specs or Scarf and Burn Up can only be used once per switchin, it's a terrible move for typhlosion