90 yamaha 2 stroke wet plug #3 cylinder

[birdseye418]

after motor was hesitating to plane I noticed a few drops of water on the # 3 plug. I cleaned it off and boat ran good until I idled for a few minutes, then hesitated again to plain. Checked the plug again had a few drops of water on it.
Ok, I replaced the head gasket and still have the problem.
Could the head cover gasket be causing this?
Please help!

[boats.net]

Check for corrosion holes in cylinder head and exhaust plate, may have hole corroded through and allowing water in cylunder.

[birdseye418]

outside of some soft corrosion/build up in the water jackets all looked good. Someone just told me they got water on thier #3 plug after getting water in the gas. Not somthing I would expect with a fuel filter and a F/W seperator not producing water.
I'll try an external tank and see if gass is the problem.