The early side carb engine had problems with fuel pooling in the intake tract between the carb and the reeds. After a period of idle, tipping or turning the plane / engine could cause those pooled drops of fuel to flood the engine causing it to die. Some people ran these engines with good results, other owners, not so great results. DLE's fix for the problem was the redesign to the rear intake version that is currently still available.

Certainly the carb may need rebuilding which could greatly contribute to the problem.