Student or Learner
"If you guys need me just yell. I'll be around."
Do we use "yell" with any prepositions? In this context it would mean ask for help.
Well, in this context, "yell" still means shout. It's just saying to shout and get the man's attention because he will be nearby.
As for prepositions, I'm not sure. I can think of situations where you can use something similar like "shout" as a direct object.
"If you need me, give me a shout/holler. I'll be around."