You will need a carb adjusting tool, see any TR6 parts sight Victoria British, it consists of an outer keyed hub to hold diaphragm in place and an inner allen key to adjust mixture. if you do not have it don't adjust it as you will tear rubber diaphragm up. My six was 8 turns rich, I was sick of adjusting and getting no results. Took it to a LBC mechanic and he laughed at how rich the exhaust smelled. My MPG were terrible and Monza tips were alway black!Oh, the location of mixture adjusting screws are under dashpot caps, at top of carbs. Hope this helps, this forum has helped me in my time of needs!