long 610: how does the thermostart work?

[Nickydubs]

I just bought a 1982 Long 610, the previous owner only started it by using the block heater, and sometimes ether. It has the thermostart plug on the intake manifold but I can't figure out how to turn it on. The tractor only has 3 switches: start button, headlights and the key. The key has 5 positions but none of them send 12V to the thermostart. I can wire in a separate switch but don't want to before I understand how the system is supposed to work.

Also, I can't figure out why there's a fuel line going to it, any information on that would be helpful as well.

 

[Winmac]

When the thermo start is powered a element glows red, the heat opens a valve, diesel fuel drips on the coil and ignites on fire.
This warms the intake air and the flame is drawn into the cylinders when cranking over.

 

[Tiberiusx]

If it's anything like my universal the starter switch goes both ways.. One way is warm weather no preheat
And the other way you move it ( to left) on mine just before engaging starter... Hold it for a few seconds .. I have done it with hood up and can see a bit of smoke .. I will usually hear a pop then I giver.. Might go through this sequence a cpl times depends on how cold