Sounds like it's "jetted" and probably by damn idiots! Turning up the idle might help, but only if the idle is set too low to begin with.
Only way to know if it is "jetted" is to remove the float bowl and check the sizes on the jets. However if the jetting was accomplished by drilling, then the numbers on the jets are meaningless. Better question is who did the jetting and why was it done?
Most of the time inexperienced mechanics think they will make it go faster by putting in bigger jets. Re-jetting is done as necessitated by changes mostly to the intake.
The carb bouncing is normal due to being mounted in a rubber intake manifold and is exaggerated when the air box is removed and the intake side of the carb is not supported by the carb to air box tube.