Dear all, my wide band 02 sensors are showing left and right banks both running too rich at 10.5 - 11.5 at cruise at 2,000, at 3,000 and all revs in between. At WOT both sides lean to an acceptable 13.5 or so.

Carbs have been rebuilt, running 30mm ventures, all float levels are spot on. Standard zenith emulsion jets. Sizes of idle and main jets I forget.

So I think my question is, what do I need to change to make it run leaner at cruise? Larger air correction jet? (Already big at 220). Smaller main jets? Other?

many thanks in advance firom any zenith 40 TIN carb experts.

Dave

ps this is in a 1975 Porsche 914 fitted with a 2.8 litre reverse rotation Chevrolet Corvair 6-cylinder horizontally opposed air cooled engine

Hi Steve, thanks for your reply so, to enriches it at WOT, is that a matter for smaller air direction jets (from 220 to 180, say)? Or is that a mater for larger mains? Or a combination.

I have ave a range of spare hets, I have the zenith technical manual, but what I don’t have is a good appreciation of what jets affect what driving condition. So I really need to have a better appreciation of the principles before doing to much. May contact a carb shop and see if I can pay them for some tutoring.