DT 65 won't run under load

[rpauti]

My motor won't run under load. It idles fine and run great in the yard with the water hose on it in gear; I can rev it up, no problem. Put it in the water at the launch and it will die after trying to give gas in gear. Things I tried: New plugs, good fire. Cleaned all 3 carbs, removed and cleaned jets, new fuel pump , hooked external tank, good fuel to carbs; clean fuel. I'm thinking timming advance on middle carb going to CDI. Also changed fuel filters.1st indication of problem was running motor about 3/4 speed, running great, then lost power and died. Any help is appreciated. Thanks in advance

[boats.net]

Run a compression test. Test for spark at plugs to see if firing on all cylinders.

[rpauti]

Sucess

Removed carbs, took them apart and boiled the throttle bodys in antifreeze forabout 5min at about 200 degrees. This cleaned them out and they run like champions......thanks for the help