Repairs 2007 Lazer Z PTO/Engine bogging issue

I have a 2007 exmark model LAS28KA604 with a 26 HP Kawasaki model 6KAXS and about 360 hours on it. My wife told me a couple of weeks ago that the motor was bogging when she engaged the PTO. I obviously went and investigated and could find nothing wrong a chalked it up to something I was not around to witness so I was chasing a ghost. Sure enough the next time I used it after running for a while when I engaged the PTO the engine felt like it was at half power. After several seconds it sounded like the clutch finally fully engaged and the engine/blades got to full speed. When I started troubleshooting I noted that sometimes it would take a really long time for the engine to come up to full speed and sometimes it would never. It seems as if engagement occurs but for whatever reason it won't come up to speed. I have already replaced the main drive belt and battery as both were near due anyways.

Also trying to locate a wiring diagram for this as well. I recently adjusted valves as well as it seems to get hung up on TDC when starting at times. The valve adjust didn't make a difference. Any ideas what to check?

Thanks for any input.