Originally Posted By Tom_Quad
STOP!
based on the description of the problem it appears that fuel is leaking past the o ring on the needle/seat on one or more carbs.
You will probably see fuel coming out of the vent on the offending carb. Don't make this harder than it is


What needs to be done to fix? Only thing that's changed is the fuel filter.

1970 EK2 T/A 727