probably dumb question, but "overflow port" dumping gas?

[porchlight]

Hi all,

I am having a problem with what I assume is an overflow port for my gas tank. I've never actually noticed this thing before, but it's like a little nub coming off of the starboard side of my boat, near the stern, pretty high above the waterline.



I'm not 100% sure when this started, but last time I was putting in gas, I noticed that every 20 or 30 seconds, this port would dump like a table spoon of gas. I filled my tank from empty to about halfway, so it's not like it was overflowing.

I took a short video of it here:
https://youtu.be/aYWDLtLXCXU

Is this an overflow port of some kind? Why would it be dumping gas like this? Should I be worried about gas like evaporating out of this port?

Any information on this port or what is happening here would be appreciated.

Thanks!

 

[alldodge]

Yes its the gas tank over flow. Gas is going in the tank and the air is being pushed out around the nozzle and the over flow. How much pushes out depends on where the over flow is connected to the tank, and how fast the gas goes in.

If gas is put in slower, this will happen less
https://www.boatingmag.com/five-boat-fuel-vent-tips#page-5

 

[Old Ironmaker]

It's your fuel tanks vent. If you are spilling gas out it maybe plugged a bit. It should unscrew. I had a plugged vent and I just blew some compressed air down the vent line and cleaned the screen off.. Wear eye protection if you decide to blow it out. If I remember right I took the gas cap off when I blew the vent line out and could hear gurgling. NO SMOKING.

 

[GA_Boater]

I would call it a vent for the fuel tank, not an overflow. That's just me. LOL

It vents air out the tank while filling and into the tank while running the motor.

It you didn't have a vent, filling and using the gas from the tank causes problems because air has to move in and out of the tank.

As AD said, filling slower may reduce the vent spit. Filling fast sloshes the gas and some is probably splashing into the tank vent pickup and out the vent.

By any chance are you filling up with a vapor recovery nozzle? Lifting the bellows a little allows more air to vent out of the tank filler.

 

[Old Ironmaker]

Yes it is a vent. Any enclosed vessel, tank, container etc. must be vented with air in order to fill it or empty it. Remember the old days when soda and beer cans had to be opened with a can opener? You had to poke another hole in it on the opposite side or you couldn't drink it. Many here don't remember that because they weren't born yet.

 

[hemi rt]

sounds like the vent line has a dip in it, at one time some fuel got into the vent line and now when filling the tank air coming out the vent pushed some of this gas out the vent. It should clear up the next time you use the boat. If the line has a dip in it you may want to raise this dip so fuel can no longer collect in the line.

 

[porchlight]

OK, thanks all! I feel so much better. First time I noticed this and thought maybe it was bad.

Thanks for setting my mind at ease!

 

[harringtondav]

Yes it is a vent. Any enclosed vessel, tank, container etc. must be vented with air in order to fill it or empty it.

Yes. Seems common sense. Until you purchase a new "safe" portable gas can. Some idiot, Darwin Award candidate BBQd himself pouring gas on a campfire from a Blitz can. The PI lawyers got hold of the liability case. Blitz couldn't afford the jury award, closed its doors and laid off 200+ workers.

The result is the totally non-functional, unusable gas cans we have today. Fortunately someone filled the need. You can buy a conversion kit with snap in vent and traditional spout for $8 USD at Menards and other big box stores.

 

[Old Ironmaker]

Isn't that how you start a fire harringtondav ? A buddy was trying to light a fire on the beach one New Years Eve. He must have poured 1/2 gallon of gas on the thing, no light, too windy. When he did finally light it there were flames 20 feet out over the lake and in all directions. He had to jump in the ice cold water before he went up in flames too. He was awarded the Darwinian for the year. It's not the liquid that will kill you it's the gas vapours.

 

[82rude]

Ive seen the old style gas cans for sale again.Slightly modded but their now for sale.Me I bought an electric transfer pump called gas buddy as I despised those back breaker epa cans .

 

[JASinIL2006]

Yes. Seems common sense. Until you purchase a new "safe" portable gas can. Some idiot, Darwin Award candidate BBQd himself pouring gas on a campfire from a Blitz can. The PI lawyers got hold of the liability case. Blitz couldn't afford the jury award, closed its doors and laid off 200+ workers.

The result is the totally non-functional, unusable gas cans we have today. Fortunately someone filled the need. You can buy a conversion kit with snap in vent and traditional spout for $8 USD at Menards and other big box stores.

I thought the non-functional spouts with which we're we're currently cursed were due to EPA regulations aimed at reducing gas cans from venting fuel vapors into the atmosphere. (The irony, of course, is that everyone I know spills far more gas than ever trying to get the vaporless spouts to actually pour gas....)

 

[harringtondav]

I thought the non-functional spouts with which we're we're currently cursed were due to EPA regulations aimed at reducing gas cans from venting fuel vapors into the atmosphere

I looked this up. You're correct, my bad. I can't help myself from slipping that Blitz story in whenever possible. Parasitic P.I. law firms and the heavy-handed EPA are the same class of hemorrhoid in my mind. But regulation writers like job security like everyone else. So stay tuned, more regs. are on the way.

Here is the fix for this stupid idea.

 

[GA_Boater]

Guys - The topic is a permanent tank vent spitting gas during a fill up. We aren't talking about portable tanks, EPA or other-wise.