RE: Walbro experts needed
+1
It is good to know whether your midrange is lean or rich. To that end, tune idle for best rpm (forget about throttle acceleration!!!!) Then slowly go to 30% throttle. Re-adjust for best rpm. If you needed to close the idle needle, midrange is rich, and vice versa!
A rich mid range can be cured using the valve cut out method.
A lean mid range needs adjusting the middle idle jet to a larger size (most times there are three idle jets)