did you double check the float level? I don't know this carb, but usually you should be able to see the fuel level. the float bowl should not be full. the bubbles are no big deal, it's just from the fuel flowing in. Also, bad throttle shaft bushings will not cause it to run rich. this will cause a vacuum leak and cause it to run lean.
If it was me, I would be looking into the carb. There is something wrong there that is making it dump too much fuel into the motor. You might make sure the needle valve is still properly attached to the float with the little wire clip or whatever it has. Make sure the float pivot rod is in the right spot. Also, are you absolutely sure the little check ball is back in the right spot? Was there a little tension spring that was with it? Is the carb center gasket still in good shape and installed correctly? The fuel level should be at or near the dot in the window on the bowl. I am running a pony on my stocker and it has worked great for a long time, so it has been a long time since I have been inside there. This is all I can think of right now. Good luck.