Kioti ck25 does not have any power.

[Gittyup]

I have the CK25 in gear. I went that way both to save money and up HP effectiveness. It spins easily even with another 900 lbs for backhoe. BTW, the CK25 weighs 3300 + 1000 or so for loader + 600 for loaded tires. With fuel, that's about 4950 lbs. Anyway, I still think there is something wrong. If it's never been serviced, that sure seems like the first thing to try. Could just be a plugged filter. Plus, you are supposed to the first service at 50 hours, and that one is very important to remove breakin shavings and what not. If the owner didn't do that first fluid change, he is asking for trouble.

 

[Fuggley]

I am a Kubota guy, but my uncle has a ck25..... Even the slightest hill would severely bog it down. Then if I went down a steeper hill the the transmission would just let it coast down the hill even though I never let off the HST pedal...

This is not normal performance for any CK-HST. You have something wrong with your tractor and need a knowledgable mechanic to properly diagnose and fix the problem.
The output power difference between a CK25/27/30/35 is imperceptible under most use and certainly not a factor in those symptoms you report.