Scag Cheetah 34hp Fuel Inj with possible fuel issues

I have a Scag 34Hp fuel injected cheetah that has recently started to lose power when the pto is engaged. My dealer isn't quite sure what the issue may be. It really loses power going up a hill and almost shuts off. It will start puffing black smoke until I either shut the blades off or get on level ground and then shut the pto off. It loses so much power when mowing thick grass also. Not sure if this is a pto clutch issue or what. Any help would be greatly appreciated. It is a 34hp fuel injected Kohler motor. It also will shake when you are sitting idle which has never happened before when the pto is engaged.

Thanks Jeremy

Sounds like a rich mixture with black smoke, does it use any oil?

What engine do you have?

I use 93 octane 100%ethanol free gas. Been using that for over 1-1/2 years. It’s 34hp fuel injected. It only does it when the blade pto is engaged.

It’s a kohler motor. It burns so hot I was told I have to use 20w50 Kawasaki oil. And it leaks from my valve cover gaskets. I’m about ready to get rid of it and go with another brand

Is there another dealer nearby?

Does it through any codes?

https://www.youtube.com/watch?v=0cu2ZUAsFg0

Try removing the plug wires one at a time.
If it dies when one is pulled but runs the same when the other is pulled then you have a dead cylinder.
Usual suspect will be a backed off valve lash or a pushrod that is not pushing.