I'm Needing To Vent

Kiggsia

Petty Officer 3rd Class
Joined
Sep 18, 2008
Messages
98
Until my two 6 gallon outboard gas tanks are getting low on fuel, gas sloshes up into the small tank vent thumbscrew, and runs out a bit along the top of the tanks, and the smell in the gas tank compartment leaks out into the boat and is sickening. Even the regular vented fumes are strong enough to be sickening. So I ran rubber hose from quick disconnect fittings on the top of each gas tank, and teed them together to a single rubber hose going to a copper tubing water trap at the outside of the boat, near the outboard motor. I can now close the thumbscrew vents which don't baffle fuel as well as they are supposed to, and which also vent in the inside of the boat. And yet I'm wondering, has this sort of fuel/fume smell inside a boat ever caused anyone else to try anything like this, probably nobody but me was ever troubled by these things....
 

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Grub54891

Vice Admiral
Joined
Jun 17, 2012
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5,908
The quick connect fittings are not designed for fuel contact. Them look like air fittings. I think they will fail. Should be using outboard fuel connectors. Other than that there is a chance to spill fuel overboard, not good, or getting water in the fuel.
Never seen anyone do that, but my thoughts would be if you are doing this would be to run the vent lines to a charcoal canister as a car has. You could get one from a junkyard, and then run a line from that to just before the carb area to pull fumes to be burnt through the motor while running.

I will follow along and see what others have to say...…..
 

Chris1956

Supreme Mariner
Joined
Mar 25, 2004
Messages
27,036
Gee, you have installed portable fuel tanks like permanent fuel tanks. Why not get a permanent fuel tank? Fumes will be vented thru the hull.
 

racerone

Supreme Mariner
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Dec 28, 2013
Messages
36,044
Those appear to be original steel OMC tanks.--------Leakage on the original factory fittings would have been caused by bad o-rings.----Easy fix.-----A lot of work has been done here for some reason.
 

Kiggsia

Petty Officer 3rd Class
Joined
Sep 18, 2008
Messages
98
Thanks for replies. The leakage definitely is not the fuel fitting O-rings, I have been very much looking for leaks there. I could see the fuel sloshing up thru the baffled thumbscrew vent, on a brand new vented fuel cap a dealer still had on hand. It was my intention when I got all this hooked up and saw if I could route the hoses properly, etc., to replace the existing O-rings in the quick disconnects with neoprene O-rings, if possible. They are fuel resistant. I'm really not thinking that this vent line would siphon any fuel overboard, the end of it is much higher than the attachment to the fuel tanks. As for water in the lines, I was thinking that my s tubing would prevent any water from splashing into the line. I,m not sure why I made it s shaped, L shaped would have worked fine. I can see by now though, that no one else would rig something like this up, but when I smelled that strong sickening fuel smell, I was not consoled thinking that every other boater would just take this in stride and not give it a second thought if they have the same condition as I did here, the smell was sickening, also for my lady friend when she was aboard. I had thought about a built-in fuel tank which vents to the rear of the boat, I even made one of the rear deck supports that was in the way of installing a large built in tank, removable with nuts & bolts rather than the original rivets. I have a 2 cycle motor, so I would have to mix my gas & oil before pouring into a built in fuel tank, a slow process at a gas station pump.I like the idea of outboard fuel connectors for venting & a charcoal cannister. I want to make these improvements soon.
 

JimS123

Fleet Admiral
Joined
Jul 27, 2007
Messages
7,952
Where did you buy those tanks? The DO look like OMC steel tanks, but the aluminum rectangular plate where the hoses are connected are certainly not OMC. That plate should have a gas gauge in the middle, and it should not have a horizontal brass fitting. It looks like someone did an aftermarket mod.

Look at the gas caps. They are OEM OMC, and they are self venting. If you have fuel leaking then the mod was done incorrectly. The fuel line connectors and everything associated with that plate should be 100% sealed. Thumb screw vents on that tank should have never been installed.

The tanks look new. Your mods are potentially dangerous. Take the tanks back and replace them with new plastic tanks that come equipped with the new EPA compliant fuel demand valves.

PS - where did you source those tanks.....metal tanks today are archaic.
 

racerone

Supreme Mariner
Joined
Dec 28, 2013
Messages
36,044
The original factory outlet fitting on these metal tanks had 3 O-rings in them.----Plus an O-ring in the connecter.---Those were easy to replace to stop leaks--No vent screw on the cap for those original tanks either.--Not sure why all this modification work was done.
 

Chris1956

Supreme Mariner
Joined
Mar 25, 2004
Messages
27,036
Gee, install a 12 gal permanent fuel tank. It will vent to the outside.

Put some oil in the steel portable tanks,take them to a gasoline station, fill them with gasoline, and by the time you drive them to your boat, they will mix just fine. Now siphon the mixed fuel into the permanent tank.
 
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