Detecting Worn Throttle Shaft

If there isn't any noticeble movement by trying to move the throttle shaft it 
with your finger - you should be able to get an increase in RPM by spraying 
some carb cleaner into the bushings - given that they are worn?   I have 
sprayed carb cleaner to see if I get an increase in rpm and the rpms stay the 
same. 

Thanks - 

Kirk 
1275