OK. Well as a general rule if an engine will only run with fuel injected into the carb….it is more likely a plugged up jet or needle/seat than a mis-adjusted screw setting. So; if you have not already done so….I would suggest cleaning the main jet thoroughly and checking the needle/seat for proper operation. Have a look at the float level while you are at it.
according to an aftermarket manual that I have here….the idle mixture screw should be 2 turns out from a gentle seat…..and the idle speed screw should be turned in two additional turns from the initial seat for a preliminary adjustment.
In the image below….#11 is the Needle/Seat. #21 is the idle speed screw and #22 is the idle mixture screw.
