1973 mercedes 450sl

my car will run fine until its driven for about 30 minutes then it will miss very bad, it seems its getting too much fuel, because it will start to smoke black smoke, could this be the switch over valve, vacume advance
or what. I welcome any suggestions.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Black smoke from a gas engine is over fueling - for sure. The motor's cold start fuel enrichment is stuck ON - starts fine when cold but chokes when hot.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Try disconnecting the connector going to the cold start injector (next to the idle adjustment), and see if that stops the smoking.
Steve

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
does it matter that my 450 is electronic fuel injected instead of manual? Does the start valve also have a vacume diaphram in it? How hard is it to find and change? Thanks for your input.
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.