If you are in powder it will run around 120. On hard pack it will build temp, the longer you run in marginal snow the more temp it will build till you are in the damage area. Running between 120 and 160 is normal. 160 to 175 I am looking for loose snow to cool it down. 175 to 185 needs to be cooled down now, if you cant find some loose snow to cool it then shut it off. 190 you are in the red zone. 200+ you are into damage.
One more thing, when ever you shut it off even for 15 minutes, when you fire it off again spin the motor before moving (applying load) for 90 to 150 seconds to allow your coolant to mix and stabilize.
Pulling the cord and pinching the throttle is a recipe for a seizure. Pistons go to max expansion and the cylinders go to max contraction when that cold antifreeze that's in the coolers hits the cylinders. Seen it lots of times. What happened?