Adjusting mixture on 300 CE?

Following some work on my 1990 300CE, it runs too rich, and is getting poor mileage. I believe there is but one adjustment to make in order to lean it out a bit. If this is so, can someone inform the shade-tree
mechanic how to adjust it, and whether there is an inexpensive meter or gauge to use, or is it just by "feel".
Thanks,
Gecko
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Motorsforum.com is a website by car enthusiasts for car enthusiasts. It is not affiliated with any of the car or spare part manufacturers or car dealers discussed here. All logos and trade names are the property of their respective owners.