Re: gas tank vent
Unless this is a brand new boat, a permanently installed fuel tank vent is always open. Prior to this year I have never seen a vent with a valve to shut off the vent. New boats that meet the EPA regs that went into effect on Jan 1, 2012 have a charcoal filter and built in p-trap, and automatic valves that close the vent system when the engine is not being run. But it is all automatic. But prior to Jan 1, 2012 the technology required that the vent be open. The point is to never have pressure in the fuel system. If the fuel system is pressurized, even as little as 1 psi, and you get a leak anywhere in the system, it will drain the entire contents of the tank into the bilge. Not a good thing. Even the new systems have a means of bleeding any pressure in the fuel system, but they do it without venting fuel vapors. Those are absorbed by the Charcoal filter.
