190 E octane level

I recently purchased a 1990 190 E. The owner said that he used regular unleaded in it but the fuel gage sign says to use premium unleaded. Most gas stations have 3 to 4 octane levels. Which one should I use?
John Mc
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
As has been said before, the words "premium", "regular" etc have little meaning. What matters is the actual octane number. I guess there is no manual with instructions?
I would follow the manufacturer's instruction. Do you think your gauge sign was applied by Merc?
I have a 1993 190 E 2-litre and it runs on 95 octane unleaded, equivalent to about 90 US. (I had timing changed by dealer when nearly new, just when unleaded was coming into the UK in a big way.)
DAS --
--
NB: To reply directly replace "nospam" with "schmetterling"
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.