Suzuki 1993 DT30 - Stalling at idle in Water

[gonad99]

Hey all I have my frist boat (yeppy for me)

anyway it has a 1993 Suzuki DT30 that is stalling when in the water at idle. When going there is not a prob and when its out of the water it runs fine.

I have cleaned the carbys, New Plugs, New fuel..

The boat was sitting for about 3 years before I brought it.

Any idea's

thanks