Here is what I did on my 1026R
The Whole throttle "range" is controlled by the linkage, there is threaded rod and a jam nut down near the engine, I brought mine down to 1,300 and it still can go to 3,200, but that is its max, which is fine. Next, I added a Engine Block heater, and I use it with a timer, or a remote control switch from inside my house. There is just NO way I am starting this engine to go plow at temp of less than 10 degrees COLD start.( I know it has a small "air heater") Cold starts to middle RPM are VERY hard on any engine. If any of you fly planes you'll know about preheaters. To bring a diesel that's sat a few days in the cold, and very cold, from say Zero degrees oF to 1500 rpms in 3 seconds is NOT a good thing. Its no wonder John Deere puts a 2,000 hour life on this engine but the gensets with same engine in the Coast Guard , In the Arctic, and Antarctic get 7-8,000 hours of use.
Couple weeks ago, and there's many more like it.. TOO cold for a 1026R ! at 1500 rpm, Even with a little hot air "
The 2025 speeds rated a bit lower, but I will duplicate the same with my new 2025