Well I'm very curious and like to dive right into these things
That's exactly what it sounds like! I also noticed that at 1/2 tank of fuel you can actually hear the fuel recirculate and drip in the fuel tank on the left side of the seat. Interesting stuff! I've noticed these little Iseki engines not necessarily start hard but if you don't give them a little throttle when it's freezing out, they sound like they are going to blow up or rattle the tractor apart for the first 10 seconds.
Diesel fuel does not atomize well when it's cold. Therefore, you must open the throttle some, to get enough atomized fuel in the mixture for ignition.
The reason it runs rough is, you do not have good combustion in all cylinders.
Here are some addition tips for you if you need them:
You can determine the amount to open the throttle by opening the throttle slowly while cranking, when it fires, note the throttle setting. You can use that setting next time, for that temperature.
You also need to use the glow plugs for longer intervals. In extreme conditions, it could be as long as 30-45 seconds. Perhaps even more in the future if they get weak.
If the engine does not start within 10-12 seconds of cranking. STOP, and begin again with the glow plugs. Continued cranking will only result in additional frustration, by way of a dead battery.
These engines are generally very easy to start cold, if you do it right.
Also, keep in mind the engine will not warm up properly at a low speed idle. You must use a high idle.
