Problem

[faint drift]

good evening, ive encountered a problem with this poor visual script; the character isnt jumping. what could be a problem

[worthy venture]

I dont think you should be setting linear velocity but add force instead

[mighty venture]

It should still have worked on account of it only setting the velocity once at the time the key is pressed.

Looks ok. Some things to check:

1. Jump Force is set to a high enough value
2. The graph is running on the right object
3. You have a rigidbody on the same object that's using this graph
4. Add a log to make sure your keypress is working, and maybe also make sure your velocity is receiving the value you think it's receiving. If it doesn't log or you're seeing zeroes, that will be a problem.
5. No errors?
6. You could show us a video of your graph during playmode, so we can see that the flow is working as it should?