Runs rich air screws wont change anything

[Leo T]

2004 yamaha 90hp 4 stroke,runs rich ,air screws do nothing primers changed. Timing correct,compression high on all four ,fuel filter plus fuel new Carbs rebuilt ,no corrosion ,floats at correct height ,no flooding its something affecting all 4 carbs #baffled

 

[boscoe]

How do you know that it is running overly rich? What are you seeing, smelling, hearing, etc?

 

[Leo T]

How do you know that it is running overly rich? What are you seeing, smelling, hearing, etc?

Black smoke at idle plus full throttle,all four cylinders plugs have black sooty residue