[Teutonics]

I'm not familiar with those carbs, but do you think the fuel in the bowl is leaking out (into the cylinders or siphoning back into the hose/fuel pump) or evaporating? If evaporating, could the floats be set too low?

Fuel pump is working properly? I had a similar issue with a riding mower that the fuel pump was just working barely enough to keep up with fuel demand, but never enough to keep the bowl full (didn't know this was the problem at the time). I could never get it to restart after getting hot. Finally the pump (crankcase pressure/vacuum actuated) got bad enough that the motor started surging (from starvation), rebuilt the pump and now it starts and runs like a champ.

Good luck!