A regulated fuel supply. 

To define the problem Current systems in use Work on the bench Results and experienced  problems

Hi res photos are courtesy of Rob van der Heijden, he took them while working on his ST20/25

Summary

The fuel regulating system I tried out works very  well, and uses a floatless chain saw carburettor as pump/regulator, combined with a standard model engine carburettor. In addition, exhaust pressure is used as reference for the fuel pressure. There is no pressure to the tank, nor is there fuel pressure with the engine stopped or being flicked over. Consequently, there is no flooding during the starting procedure. Due to using exhaust pressure regulated fuel pressure, fuel flow is engine load dependant, and good running is achieved under all conditions.