Fuel leak at fuel bowls

Use a paper towel or blue paper shop cloth to be sure the leak is at the inlet.
Slip it around the fuel bowls to check there too.

The nylon washers are acceptable but change them out when you can.
You can try snugging them up some more.
When the nylon gets hot enough it will begin to soften and the torque is lost. It takes an awful lot of heat in the engine for the carb itself to get that warm, but I've had it happen.:eek: :BangHead: