6 gallon gas tank no vent??

[MakoNY]

Recently bought a 13' skiff (30 hp Evinrude) and the 6 gallon tank it came with doesn't seem to be venting. After a couple of days of sitting I go out and the tank is noticeably full of positive pressure and when I release the cap it releases it.

I thought these little 6 gallon tanks were supposed to have a vent in the cap. It's been a long time (30 years) since I've had one. I've noticed that sometimes the tank will make a weasing or groaning type of noise and thought maybe there was a vent in the part where the line connects and it has a small fuel gauge, but that doesn't seem to be working if there is, at least not consistently.

I assume if it isn't venting positive pressure then it won't vent negative pressure either when running, which I assume will cause an issue, although it hasn't seemed to yet, and I've run it a good amount since I've gotten it.

Is it possible it's not the right cap on the tank or do they sometimes vent through the connector/gauge part?

It's a Systematched OMC tank, not sure how old.



Thanks.

 

[kfa4303]

Re: 6 gallon gas tank no vent??

Hi Mako. That's odd that it doesn't have a vent. My 6 gallon tank has a small, black plastic, thumb screw in the center of the main cap. Perhaps yours is similar. Do you have a pic?

 

[Home Cookin']

Re: 6 gallon gas tank no vent??

there are lots of them made with no apparent vent. real easy: leave to cap loose while running. I have old plastic tanks that do this and even older metal ones.
You can also leave it loose while sitting in the sun to prevent the pressure issues. Highly unlikely rain will blow up in there.

 

[MakoNY]

Re: 6 gallon gas tank no vent??

But what about gas coming out when you bouncing around in chop? I fill it before I go out, first bit of chop I hit and that gas it gonna be everywhere.

 

[Don Hansen]

Re: 6 gallon gas tank no vent??

If it's a metal 6 gallon Evinrude tank look at the connector on the tank. You should see a little pin that gets pushed in as you attach the hose connector. That's the automatic vent. The 6 gallon tanks had them but the 3 gallons you did have to open a vent. Even with the 3 gallon tank, the vent hole is so small that unless you over fill the tank gas is not going to go everywhere.

DLH

 

[Sea Rider]

Re: 6 gallon gas tank no vent??

Had same tank used on a Evi 15 HP, always wondered how air got inside of tank, used it with cap lightly loose, tank was not filled to full capacity to avoid fuel spills on deck when on choppy seas.-

Happy Boating

 

[JimS123]

Re: 6 gallon gas tank no vent??

You have an oldie but a goodie. Its simply the best gas tank ever invented. It's green and sustainable even before they ever thought of those terms.

Leave the cap tight. It will self vent. If pressure builds up due to heat it will vent if necessary, but not let out harmful vapors as long as the pressure is safe.

 

[Home Cookin']

Re: 6 gallon gas tank no vent??

But what about gas coming out when you bouncing around in chop? I fill it before I go out, first bit of chop I hit and that gas it gonna be everywhere.

never had that happen to me and I spent my youth jumping tugboat wakes.

 

[Chinewalker]

Re: 6 gallon gas tank no vent??

LEave cap tight. As noted above. the vent is in the fitting. Two pins - when connector is hooked up, one lets fuel out, other lets air in.

 

[seahorse5]

Re: 6 gallon gas tank no vent??

MakoNY,

The EPA requires all marine gas tanks to be sealed for up to a certain amount of pressure to limit any vapors from getting into the air. Even new large boats with built in tanks have to be pressurized or at least have a carbon canister to catch the fumes.

In the heat of the day it is normal for the tank to expand quite a bit. That is one reason why the manufacturers recommend removing the fuel connector when you are done using the motor.

You can read more about these regulations at epa.gov

 

[MakoNY]

Re: 6 gallon gas tank no vent??

It's not a metal tank it's a plastic tank. It says OMC Systematch Dura-Tank Essence. Here are some pics. There are some little pins where the fuel line connects, I was thinking those were a vent system.

 

[MakoNY]

Re: 6 gallon gas tank no vent??

Sorry posted before I saw the newer posts. Ok so I guess those pins in the connector are the vent. So they work when pressure gets to be too high and it will then release some? One is for letting high pressure out and one is for letting air in?


Thanks.

 

[MakoNY]

Re: 6 gallon gas tank no vent??

The only thing is the pin on the right in the pic above doesn't get pushed in by the fuel connector, it sits right up against it but it isn't depressed. Is that by design?

Just curious as to how this works, not that it's a huge pressing issue.

Also I assume by removing the fuel connector when not in use you mean at the engine, correct? If I were to remove it from the tank then the one pin it does depress wouldn't have anything to hold it in.

Thanks.

 

[moving violation]

Does anyone know if a replacement connector/gage assembly (pictured above) is available anywhere? I couldn't find one on the Evinrude site. Thanks in advance.

 

[Sea Rider]

That's excatly the same OMC tank used to have, the left pin is only for the hose end connector to lock there, the other one is the fuel pin. When cap was completely screwed while sittting at any heated environment, the tank used to get so darn fat that could be rolled onto any flat surface as a deck or floor including fattening when leaving tank on car's trunk. Oinc, oinc tank

Happy Boating

 

[WIMUSKY]

This thread is almost a year old. moving violation you committed a forum violation, please start your own thread..

Thanks
WIMUSKY