If you are in the Mid-West and need this serviced performed Griswold Aviation in Marshall, MI (KRMY) can do the adjustment for you. He specializes in Skymaster's and has set up injection systems. Info at :
www.griswoldaviation.com
FYI, the document (pdf) above is referred to as SID but not to be confused with the SID's that Cessna has written for the Skymaster Service Manual. The Service Information Directive above is not associated with the Supplemental Inspection Documents that have been discussed as of recent on this board.