I just switched my Gen 1 Merc control to a Gen 2. Although you need new cables, it is a much smoother control.
This is the control I purchased for my outboard:
http://www.ebay.com/itm/Mercury-New...3964&clkid=1096020736622561819&_qi=RTM2067267
The linked info inside post #4 may help with where to find the part numbers to help match the correct design shifter you're looking for. You are looking for "MCM".How would I know if I have a GEN 1/2 control?