the only way they got enough heat into the engine to get the oil moving was to take a hibachi full of glowing briquets and set it under the oil pan for a while.
there are youtube videos mostly of Russians setting up whole bonfires under their tractors to get them warm.
I have to admit as an old fireman, not something I'd likely do. But then if I was freezing to death...
what an advertisement for synthetic oil though. Consistently the reports are cold engines start more easily.
You've got a reduced capacity (due to cold) battery NOT trying to turn an ice cold engine through syrup.
lots of videos about guys with diesel equipment they have to come rescue with gasoline powered equipment because of fuel
gelling. I can't imagine having a diesel tractor or generator in below zero weather without an engine block heater on it all the time.
But some sheds don't have them. Nor do jobsites.
Nice if your gen is wheeled and at least you can keep it in a semi warm spot and then run it in very cold weather.
But for those like mine that don't move, best I can do is keep the best synthetic oil in there and run a smart charger on my battery
twice a year. If my 22kw doesn't start due to a dead battery, I'd drive my truck carefully around the plantings and jump start it.
Unless you have a portable jump starter. I find those combo air compressor, inverter, jump starter units out today to be just marvelous to pack away in the truck. I grab it all the time for something. But it isn't going to start my 999cc engine. Or would it...

Now that would be a fun test.
It's not the big commercial jump starter but the typical three in one or four in one. Seems like they are putting phone charging ports everywhere now. I expect my next toaster to have one.