Not sure where this tube connects to

that hooks to the brass injection nipple on the carb. it's missing the little brass retaining ring though, maybe a small tyrap or tie wire would work ?
it either needs to be connected if you're using the oil injection, or capped off if you're premixing your fuel oil ?
it will suck air and fry your shiz if left open.

I'd also make sure the oil pump is bled and pumping oil before reconnecting it, key off and kick until oil comes out, or there's a bleeding procedure in the free manual download here ...
https://www.blasterforum.com/thread...ervice-and-owner-manuals-free-download.17325/


Capped off for premix in this pic, but hose goes on there if using the injection