Cheers mate, Its the one in the pic attached - silver sleeve. Also whats the brass one to the left? does it come out or is it pressed in?
also I have heard 1/2 turn for the airscrew from factory and 1 1/2 and also 2 - 2 1/2 quite a range. Mine was set at almost 4 from PO but I suspect because of an overall lean condition which I'm trying to solve