Johnson 150 runs rough, fouls plug

[MIhunter]

I have a 2000 Johnson 150 j150VXSSS that has run great until this summer. After about 1/2 hour of running(great) the motor acted like it was starving for gas. I had the carbs cleaned, replaced the plugs, fuelfilter, and emptied the gastank, and refilled w/new premium fuel and fuel stabilizer. After about 1/2 hour the problem returned and the bottom left plug was fouled...Help please

[Jwellcraft]

Is the plug fouled with fuel/oil only? Make sure it isn't water because you might have a damaged base gasket which will allow water in the bottom cylinders.