1997 50 HP johnson bogging

1997 50 HP Johnson (J50TLEUC) Starts fine and sounds great in the yard. But once we get it to the water and under a load. The motor bogs way down when we throttle up and try to get up on plane. Doesn’t die, just seems to loose power like we throttled it back. We seem to only be getting to about half throttle. No missing or back firing. Compression is 120 on both cylinders.
We have changed the fuel, fuel lines, fuel tank, all fuel fittings and rebuilt the fuel pump
( non-VRO)
We rebuilt the carbs, replaced the kill switch, spark plugs, coils & power pack. Nothing seems to make a difference.

History on the motor ?---------Did it sit for a long time with fuel in carburetors ?---------Did you remove high speed jets from bottom of float bowls to clean them ?----Did you check reed valves when carburetors were off ?---------They all sound good on a hose ( even when running on one cylinder ) and it means little.----Do you have the correct prop to fit the boat ?

with all you've done, it kinda sounds like water getting to the cylinders. just my 2 cent