Nissan 50hp NS50D 2 stroke help

[jmurray109]

I have a 1992 Nissan 50hp 2 stroke and was looking for help. Recently due to the rain, and slow leaks, the rear transom on the Rib was submerged. This caused the bottom 1/3 of the motor to be submerged. I have cleaned the motor and carbs, but still having trouble keeping the motor running. I also replaced the spark plugs and made sure the fuel/filters were clean.
It will run only at "full" throttle, but as soon as you throttle down the motor will stop. I can keep the motor running at 1/2 throttle only if I constantly manipulate the choke "on and off". The compression for all 3 cylinders is 69, 70 and 71. I believe this might be low. I also noticed when running at full throttle, the bottom 2 carbs are wet (fuel/oil), but the top carb is dry. I have checked the fuel flow and the float for this carb and it is getting fuel. I am a volunteer for a youth sailing group from Dana Point and this rib and motor is used as one of our safety boats. It was donated several years ago. This motor is perfect for our program, but I believe it might have reached the end of its life. Any advised would be appreciated. Or if you live in the area of Dana Point and have the skills we would appreciate the help.

[a64pilot]

You have a carburetor(s) problem, sounds like the low speed circuit is clogged, that is why it will run on choke at lower throttle.