I have a 18 hp Kawasaki motor for my lawn tractor. Need help been experiencing a loss of power, plugs fouling up and some black smoke. I cleaned the carb as best as I could. changed out plugs, opened up drain screw near carb to empty out the gas in the line, checked fuel filter. Still no changes, what do i need to do next. Looked around the motor and for some reason there is a governor. I just need a little bit more power to run my deck. Don't know much about engines but I try, didn't pay much attention to Dad when he was in the garage, thought the stuff he was trying to teach me was lame, boy am I regretting that. Ithinking about draining entire fuel system maybe I got some bad gas or will fuel additive do the trick. Please help don't want to take it to a shop, want the satisfaction of fixing it myself.