I made the experience that the 34PBIC3 does not work properly on the small 595 engines, especially on very low revolutions/speed.
that is, because there are three drillings in the idle systems to the throttle whereas there are two on the standard 'not "3"' - PBIC.
I always wanted to try to close one of those drillings to see if it could work with the PBIC3, but I have not found the time for it...