I have an LX279 with 17 hp liquid cooled Kawasaki. Recently when I engage the electric pto the rpm's drop significantly, almost by half, judging by the sound. It's enough to turn the blades and cut, but barely. I ran it for 3 or 4 minutes like that and it suddenly went back up to full rpm's. I took the carb off and cleaned it thoroughly. I've cleaned hundreds of carbs and I'm confident it's clean. I started it and it runs smooth as silk until I engage the pto and the power still drops. Could this be the pto going bad?