If Daedong detuned the engine, they would reasonably give it a different name and rating no?? That's what every other diesel manufacturer does. Why does Kioti list the same model and same displacement??? The DK series motor was bored and stroked to get higher output. That one was naturally aspirated. If Daedong is varying the turbocharger psi to modify output on the 3F183T, then there absolutely will be implications for duty cycle. Why is there no mention of this in any of the Daedong/Kioti literature? Is the 3F183T rated for continuous, medium or intermittent duty at 60hp??? Surely you went over this with the dealer before ordering??? Do you even know whether your engine is actually 1.8 liters? I cannot find any technical info at all that isn't rehashed news releases with limited data. Of course you will undoubtedly have thought about all of this before I did so please don't keep us in suspense any longer. How exactly do the four versions of the 3F183T differ from each other?
Regarding the cooling system, I don't care how efficient it is, it is going to require cleaning of the radiator screen to keep it efficient when mowing. If I recall the laws of physics properly, the 60hp variant will put out significantly more heat at PTO RPM than the 45hp model. It stands to reason that the 45 will therefore be more tolerant of chaff in the radiator screen and remain at normal operating temperature longer. Your mower looks brand new so perhaps you haven't experienced the pleasures of monitoring the temp gauge while trying to mow midsummer. And, remember, it was the same engineers in Korea who designed the cooling system for the DK. I assure you that cooling system works fine until the radiator screen gets clogged so I'm pretty sure the same issue will occur with the NX.