Australian Car Repair Issues? Ask an Auto Mechanic for Answers ASAP
I'm sorry you have not been attended to as yet.
Sounds like your fuel pressure is too high, one pump is causing high consumption, but not quite flooding, the second is just higher causing the flooding condition.
The best way to combat this is to add a pressure regulator before the carburettors.
SUs like up to 3 psi, and you find a steady 3psi all the way through the rev range to be ample.
Hope this helps.