help 1990 yamah 40SD 3 cylinder

I have a 1990 yamaha 40hp 3 cylinder (40SD model number) it is only running on 1 cylinder. I have cleaned all 3 carbs. replaced all plugs, cleaned/swapped reed valves, and have compression @105 psi on all 3 cylinders.I have also swapped plugs wires to check if it could be those but they all work on the good cylinder I know it is only running on one cylinder b/c I have taken spark plug wires off the top and bottom plugs and there is no change in in engine performance. I am truly at a loss for what could be causing this. I have spark, compression and fuel. This is not a trick question this is really happening. if anyone can help I would greatly appreciate it.