Injector Pump Fuel Adjustment

[Isuzu1989R]

Hello guys, thanks for adding me to the group.

Simple question for you all, recently picked up a car carrier with the 4BE1 engine in it. Previous owner replaced the injectors and adjusted the fuel setting but failed to replace the air filter ( looked like it was in there for 10 years and a pile of rust fell out of the canister when I pulled it out )

Question is for less mucking around for me the screw with locknut, in for increase or decrease on fuel ?