2003 Mercury 90 HP OB 4 stroke. Had a issue with starting......it would turned over but had hard time starting. Checked some vacuum lines and mistakenly pulled one out that goes behind the carbs (really hard to get to). On this vacuum line there's a kind of check valve where you can blow through but not suck air into. Motor immediately starts right up now that this line isn't connected but want to reconnect to see if I broke something loose and it'll start when hooked back up. Anyways, my question....what is this and what is the purpose of it? I know it's vacuum but to where since I can barely see the port to where it gets attached. Thanks.
