Outdoor Power Equipment and Small Engines - Kohler 16hp idles will not accelerate stallsout

have cleaned Walbro carb will solenoid, now will start and idle but when you open the throttle to mowing engine rpm it stalls like it starving for fuel. runs also when choke almost completely closed in choke position but never really smooths out impossible to find a functional choke position. Engine runs nice and smooth at idle.
Question.... is my problem the carb itself. ..will replacing the throttle butterfly shaft and bushion improve the vacuum on intake. they don't seem worn but can sense a slight movement of the shaft within the bushion.
Any assistance appreciated

A badly worn throttle shaft can certainly cause a lean carburetor condition but since I can't feel the play in such myself I can't advise you well if the amount of play you have will, indeed, be your trouble. And since you didn't indicate how old or on what application the engine is used it's hard to say if either would be likely for you to be concerned with it. Based on the fact it has a fuel solenoid I'd say it is relatively new and that the play you have is normal or at least not troublesome. I'd be more inclined to say you have a restriction in the carburetor and need to clean and recondition the carb.

With you having the choke nearly closed at full throttle, it is an indicator that you are not getting fuel through the main high speed jet. Take a fine wire and make sure all the holes are open in the jet that the fuel solnoid screws into. The fuel solnoid shuts off the fuel being drawn into the engine when you shut it down so the engine will not back fire. You may have to look closely as have not indicated the Kohler egine numbers so we could tell you exactly where the jet is located. Good luck.