The adjustment screws are easy to see once you remove the round chrome vacuum chamber covers right below the tank.. #3 is the base carb and is not adjustable. Leave one hose connected to #3 and adjust the others (in 2 phases) to match it. Shut off and hook up #1,3,4,5 and sync to #3. When done, pull off #1 & 5 and put on #2 & 6. Start engine and sync. The engine should be warm and level (on a lift).