Or looking at it another way, like down onto the top of the carb, you do turn it clockwise to enrich and anti-clockwise to lean as you say. PaulH. ----- Original Message ----- > You "screw it up" to lean it... That's per my SU manual. > > when adjusting the HS4 carburetors on the MGB is clockwise enriching the > mixture? counterclockwise going to lean?