Question about fuel tank vent.

[porscheguy]

Question about fuel vent.

ive got an older boat that does not have a modern sealed fuel tank with an evaporative emissions can. It just has a vent. It’s a stander moeller plastic tank.

the question is, does the vent work both ways? Or is there some kind of check valve in it? If I blow air into the tank it escapes just fine. If I blow air into the vent, it feels like there’s a restriction. Is that normal? If the tank vent can’t draw air in, how does it not result in vacuum as the engine draws fuel out?

 

[harringtondav]

I wasn't aware of EVAP boat fuel systems. My boat and others I'm familiar with have an open vent with a rain/water cover. In fact many fueling and fuel delivery problems come from a plugged vent.

 

[Bondo]

the question is, does the vent work both ways?

Ayuh,.... It should be free flowin' in both directions,.....

 

[porscheguy]

I wasn't aware of EVAP boat fuel systems. My boat and others I'm familiar with have an open vent with a rain/water cover. In fact many fueling and fuel delivery problems come from a plugged vent.

I didn’t realize it either until I started looking it up. Sometime in the past 10-15 years they started doing EVAP on boats.

 

[porscheguy]

Ayuh,.... It should be free flowin' in both directions,.....

I’ll have to investigate further. I’ll probably replace the vent anyway.