mystery hose

[cutter26]

I found out what the hose coming off the bottom of my manifold is for on my 89 40hp vro. It is a return line from the air box in case any gas spills out of the carbs while the engine is tilted. The funny thing is my motor doesn't have a nipple anywhere on the air box. From what I've read it doesn't effect engine idle or running because its a open line anyway.

[Elton Smith]

That may be your overboard indicator.It will leak water after it is warmed up to let you know your thermostat is open.