Question: I recently bought a new boat and over the weekend I was looking around in the electrical and machinery spaces to get a feel for where all the service items are located. Now I’m mystified. This silver can is in the compartment where one of my batteries is located.

It has a fuel line marked USCG Certified etc. going into it, and one coming out of it to the side of the boat. The line coming out is connected to what appears to be a vent fitting on the outside of the hull. What is this, and do I have to do anything with it? I can’t find any information in my owner’s manual.


This fuel vent line filter is designed to minimize the amount of gasoline fuel vapor that exits your tank via the vent system.

Answer: Welcome to the world of EPA EVAP Control! What you are looking at is a charcoal filter for your fuel tank’s vent line. It is designed to minimize the amount of gasoline fuel vapor that exits your fuel tank via the vent system into the atmosphere, and it’s one of a few components that have been added to your new boat’s fuel system to comply with new EPA standards.

This canister is designed to prevent any raw fuel from spitting out of your fuel tank vent when you fill your fuel tank to the top. If it has been designed correctly, it should not ever actually get any liquid fuel into it and will not require any service. If it ever does get contaminated with raw fuel, it would probably need replacement.

Incidentally, you have one of these units on your car. These have been used on automobiles since the mid 1970s.