Connects to the reciever? care to rephrase ?
I don't own this engine, but I know enough to say that you skimpy (reminds of Ren and Stimpy) is right. The other needle is the mid-end needle. Never touch that needle until you are an official afficionado of engine tuning .

You really don't need to touch it, b/c the gain for adjusting this adjustable spraybar (technically, that is what this is) is low, but the consequences of screwing up when adjusting the spray bar can give you the biggest headaches.