I have clearly diagnosed this and NOT coming from the carb bowl vent lines. With a new installation, the experts said to flush the fuel system/carb for new installation debris, make sure the float valve needle is clean/seating (we took it apart and cleaned plus saw a slight even wear ring with a magnifying glass around the tip to assure it is seating). We synced the carbs. All the suggestions. Still the same problem. Fuel coming out the air filters.
My ROTAX mechanic thinks it is too much pressure overriding the float valve needle so I am going to install a pressure gage to see where we are at. My research shows that if there is too high a pressure you can adjust/decrease fuel pressure by changing/increasing the orifice of the adapter sleeve (which I assume is the restrictor jet in the installation manual 73-000-00 page 3) on the fuel return line.
Does it sound like I am on the right track? If I have too much pressure, would this cause fuel to be coming out my air filters? Any other experience with this?