Issue with JD Zero turn

[retiredfirechief2023]

I have a surging problem with Z335 M. It surges after it warms up a bit but when I engage PTO, not so much. I have cleaned air filter, fuel filter and have a good flow of fuel out of fuel pump. Any ideas?

 

[Alan]

That surging easing up once the PTO kicks in is an interesting clue since it points toward something load related rather than a straight fuel issue. Sounds like you've already ruled out the obvious stuff with the filters and pump. What's it doing exactly when it surges is the engine speed hunting up and down on its own at idle or under light throttle?