Seems like we might be straying a little and going from "starting procedure" to "starting procedure in extreme temperatures".
I would imagine that if I lived in the northern climes, it would be prudent to modify starting and operating procedures. I doubt that I would start anything without some type of preheating. Many years ago, I literally blew the oil filters off my cars by cranking them up without preheating.
In a previous job, I designed substation transformers. We had a standard manual that went out with all transformers. The only time I had to write a custom manual was for one that I designed for northern Alaska. In extreme cold, sometimes things are a bit different. That series of transformers would have destroyed themselves if they were started in the normal fashion.
In the part of the thread about what rpm is half throttle, I would have thought folks would report that "my tractor turns x rpm at half throttle." I am reasonably confident Kubota means "grab hold of that handle and move it somewhere close to the halfway point."
As for the gentleman that did the test with the oil pump: I was very impressed everything he said. He is sharp as a tack, and he knows what he is talking about, and that shines right through.
Most modern engines have a bypass in their filter in the event that they may somehow become clogged, but also to prevent them from simply blowing apart their shell. I have seen these shells fracture, but mostly, they will be pushed off of their threaded nipple until the rubber gasket looses its seal, and the oil spills out. I have seen this in hydraulics and in engines.
Also, it should be remembered that most modern engines have a oil pump relief valve that sets the maximum pressure that will be obtained, regardless of the temperature of the oil. Although pressure could get too low due to high oil temperature, or low pump rpm, it ought not get too high, regardless of temperature. If you believe your climate precludes this, then certainly you will need a gear drive tractor, not a hydrostatic one, since those reliefs would be likewise effected.
Some oil pumps can have difficulty establishing their prime once lost. Many pumps will lose their prime over time. High viscosity oil in a pickup tube makes it even harder. Starting at a lower rpm certainly does not help this situation. In this case, you are dealing with a pump that is pumping air, not oil. Once the air is displaced, and some vacuum is formed, and the oil finally gets up to the pump, then it begins to function as the reliable fixed displacement pump we all rely on.
If if you want to talk about a diesel, you can say they burn diesel, and they have high compression, and they have high injection pressures to compensate. BUT: beyond these common things, you must then specify WHICH diesel. A VW that can turn nearly 6000 rpm, a Kubota that can turn 3200 rpm, or a big industrial that can turn 900 rpm? Each is different, and each has their own manual, which will tell you many things, including how to start it.
My BX has a fixed displacement lift pump that acts as a pilot pump for the hydrostatic unit as well. It ought to warm up a bit before it is put to work. If will warm up much faster at half throttle than at idle, since few if any of the reliefs are being challenged at idle. Anytime a hydraulic pressure drops with an actual flow of fluid and this happens while not shifting a heavy load, that power is going directly to heat. Even so, it still takes a while.
