Fuel vent dripping fuel

[PatinIdaho]

Ok so a lot of us have this problem.
I could deal with it until yesterday when i was at the lake and we were at shore and swimming. Noticed gas was starting to drip out the vent into the water. Totally not good! having gas dripping into where your swimming/fishing or environmental reasons.
So im thinking maybe i could add some kind of serge tank in the vent hose that acts like a car radiator over flow tank allowing it to catch the fuel but still allow air out as it holds the gas in the serge tank and pull it back into the main tank as it cools or gets used.
My fuel vent is mounted high up on the transom just below the rub rail. Im guessing maybe 2ish feet higher then the tank and could mount the serge tank about 3 inches lower then the vent.
Can't seem to find anything online or maybe im barking up the wrong tree here but it seems like a easy fix.
The only potential problem i can see is when your filling the boat as the vent might not spit fuel anymore letting you know its almost full.

I know some are thinking just put less fuel in it. Its a BIG lake and i never know how far we are going to go our how long we are going to be running the engine
Using google to measure distance im usually running about 20 miles for a complete round trip sometimes even more so i need that much fuel. Just getting to our usual spot is 7 miles from the dock.
Thoughts, Ideas?

 

[tpenfield]

Yea, fuel/oil discharge on the water is a no-no.

What boat are we talking about???

There is probably something wrong with your vent line . . . and expansion in the tank was forcing fuel up the line rather than allowing it to vent. You are right about having too much fuel in the tank as that can contribute to vent line overflow.

Fuel systems must be USCG approved (in the USA), so that is probably why you have not found much info about modifications, etc.

It would be best to figure out if there are any problems with the vent line itself, and also be sure not to top off the tank.

 

[PatinIdaho]

No Title

It is a 1979 Trihull From picts i have seen posted here and google images it is correct for these years boats.
Vent and fill hose is correct with no blockage and work properly

 

[shrew]

If the fuel vent is dripping fuel, then it would indicate that the tank was overfilled. More accurately, it was filled to FULL, from an underground tank where the fuel temp if fairly low. Then when the boat fuel tank was filled to full, the fuel began to rise in temperature (it's not longer in an underground tank). As the fuel increases in temps it expands until it begins to purge from the vent line.

1) To fix this, run the boat for a while and burn off some fuel.

2) Try not to fill the boat beyond 90-95%. In hoter temps, shoot for 90%.

This has nothing to do with an improper vent hose. This is a very common mistake.

 

[PatinIdaho]

No Title

Yeah i hear ya. Its just a crapy design.
Was thinking something like this but guess its not gonna work

 

[hostage]

I have had this problem a couple of times, it normally happens in the late fall when I winterize my boat. When the boat warms up by spring then it starts to come out the vent a little bit. I too am going to not fill my tank all the way up, but it is hard to figure out how full is full...

I don't have this problem any other time as I keep my tank about half full/empty. No reason to haul around another 110lbs of weight, it is not like I use a lot of fuel. It can take me a month to get my fuel to about half way empty.

 

[PatinIdaho]

Some days i will burn most of the fuel. 1/2 a tank will not be enough.

 

[tpenfield]

There are some things called "surge protectors" for fuel vent lines, but it may not be the full solution to your issue.