Onboard fuel tank vent

[Puddy905]

Ok. So I have a 17' Campion ski boat with a 16 gallon fuel tank in the bow. It has a vent which goes through a hose to a fitting on the side of the boat. I was just wondering how this is supposed to be setup. The reason I ask is because everytime I fill the tank past 3/4's full, it leaks out the vent, whenever the boat goes over a wave, or hit a bump on the trailer. It's really annoying, not to mention how horrible it is for the environment! Any help would be appreciated!!

 

[Chris1956]

Re: Onboard fuel tank vent

Yeah, Some fuel tanks do that. Especially flat type tanks. Is the vent fitting on the forward part of the tank? If so, that is probably the best you can do. Can you wire up the vent hose, so it has a hump in the middle? That can help as well. Another trick is to put some restrictor in the hose to stop splashing. Maybe some plastic wool like folks use to clean dishes. It has to allow air to pass thru, but be a slight barrier to liquids.

 

[superbenk]

Re: Onboard fuel tank vent

You should have a full loop in the vent hose. That should keep water from splashing in and fuel from splashing out. That said, mine had that & I still had the fuel leakage problem you have. I ended up getting a ball check valve that is designed so the ball floats and plugs the vent if fuel tries to flow out. Works really well & haven't had any fuel spills since. Only cost me about $12-$15 if I remember correctly.

 

[grego]

Re: Onboard fuel tank vent

others have the same problem, SO!!! do a google search for an "after market" fix for your problem. I would say that you will find something.

 

[asm_]

Re: Onboard fuel tank vent

I also have a tank vent, but never had problem with leaky fuel. I am wondering how my is setup different then yours. Since I didn't install the vent, I can't say if there was a loop in the vent line, but I know for fact that my vent is at least 6" - 9" higher then top of the tank. With this setup, I don't really see how the fuel can have any chance of getting out.

 

[Mark42]

Re: Onboard fuel tank vent

Check for the loop in the vent line that other have mentioned. If you don't have the space for it, then try one of the inline ball check valves.

I installed my tank, and made the vent hose rise up higher than the fill, then drop down about 8" to the vent. When I fill the tank, about a half cup of gas will shoot out the vent when full. But on the water gas goes not splash out.

Another boat I installed a tank on the vent went straight from the tank up to the closed bow with no loop or riser. That vent spits gas until the gas level drops about 3 inches in rough water.

 

[rs1lollie]

Re: Onboard fuel tank vent

I think this is what you are looking for Puddy905.
http://www.iboats.com/Attwood-Fuel-...68122015--**********.022597150--view_id.37945

 

[Puddy905]

Re: Onboard fuel tank vent

Thanks for all the great replies guys. To answer some questions, the line has a slight incline from the top of the tank to the acutal vent, but obviously during waves, that changes. There is no loop, and there is maybe only 4 inches between the line and the bottom of the deck, so maybe I will try a small loop first. I will also order an inline "surge protector", but I think the loop makes more sense, as it would surely keep fuel from "sitting" in the vent line and blocking it. I guess the best way is to do both a loop, and then a surge protector right before the vent!
Thanks again everyone!!

 

[Home Cookin']

Re: Onboard fuel tank vent

a loop will hold fuel and block th event; you want a swan neck.

surge protectors are not recommended by some.

suggestion: replace the fuel fill cap with a vented one. the over-board vents are a rick of water getting into your fuel.

 

[Puddy905]

Re: Onboard fuel tank vent

So. I don't think a loop will work. The current vent is a "goose neck" style. It comes straight up off of the tank in about a 4" rise, then slopes down on a 45 degree angle (following the deck) to the vent on the hull, which is parallel to the top of the tank. I really don't understand why it is leaking the way it is. There must be a ton of pressure in the tank...but that means the vent isn't working properly. I may try replacing the cap on top of replacing the vent line and putting in a surge protector.