So this is a 1974 18RC motor. Had the shop go through her and check the timing, points and tune the "last" carb. But that unit will not drop down from the 12k idle and thus will be going back to the rebuilder. Now the new carb is on with no vacuum leaks, idle drops down just fine but once i got the idle to the 750/800rpm range it seem a bit lumpy. Here is a short video of the motor idling. Thoughts and opinions?