Vented cap gas tank question:

[pecheux]

Good day,

I have this small 12 footer boat + 6 hp sitting at a dock with the gas tank sitting in the boat all true the summer months. I had a non vented (or automatic vented) OMC metal gas tank that has no vent screw on the cap therefore I presume that no water could infiltrate the tank and mix with gas/oil when it rained on it.

Now I would like to change the tank for a newer plastic model but they all have a venting screw on the cap that needs to be a the open position while running, more so when under the sun I guess.

Question is: Can water infiltrate the tank via the venting hole while it rains on it ? or is there something in the cap that prevents that from happening ?

Thank you

 

[Greg Mrozinski]

Re: Vented cap gas tank question:

My tank's vent screws have a large top on them so that when you unscrew them the hole is still covered. Plus you don't need to uncrew them far to allow air to enter or fumes escape. I don't think water will get in in.

 

[F_R]

Re: Vented cap gas tank question:

If it does get in, it will be on the order of a few drops. Not to worry, the motor can digest that much, and does it all the time anyway. You just don't know it.

 

[JimS123]

Re: Vented cap gas tank question:

Why on earth change the tank? Plastic tanks suck. Keep the metal one, or if its no longer servicable, replace it with another metal one. Costs a few bucks more, but boating ain't cheep!

How bout safety? Google OSHA, DOT and plastic gas cans. What you read will convince you for sure!

 

[steelespike]

Re: Vented cap gas tank question:

I bought plastic tanks circa 1999 I wish I had gone with either fixing up my old metal tanks or new.From day one the gauges weren't accurate and soon stopped working all together.The hose connector was difficult to use And the tanks were an odd shape when carrying them by the handle they were on end.

 

[pecheux]

Re: Vented cap gas tank question:

If it does get in, it will be on the order of a few drops. Not to worry, the motor can digest that much, and does it all the time anyway. You just don't know it.

Learn something new every day, I thought the motor would sputter and stall if a single drop of water passed in the carb & pistons. I do have a running portion (25% or storage qty) of stabil in every tank of fresh gas/oil mix though.

Tx

 

[pecheux]

Re: Vented cap gas tank question:

Why on earth change the tank? Plastic tanks suck. Keep the metal one, or if its no longer servicable, replace it with another metal one. Costs a few bucks more, but boating ain't cheep!

How bout safety? Google OSHA, DOT and plastic gas cans. What you read will convince you for sure!

Want to use the old OMC tank with my other fishing boat on a trailer (avatar) I did NOT know those OMC metal tanks were still available ??? Are you sure ??

Replacement plastic tank I saw was at a Mercury dealer, labeled Qwicksilver, cost approx $ 60. for that kind of money and name I would have expected descent quality ???

 

[Home Cookin']

Re: Vented cap gas tank question:

I recall seeing new OMC metal tanks for around $70, about 3x the cost of plastic.
Back when I used the metal tanks I left the cap loose while it sat in the sun.
On the plastic ones, as was said, you only leave the top loose a little bit. If still concerned, put a baggie loosely over it

 

[Cannondale]

Re: Vented cap gas tank question:

OP....I'm wondering if your OMC motor is old, meaning your metal tank is one of the old pressurized tanks Evinrude/Johnson used for years waaaay back when. No vent but had dual fuel lines running to the tank. If that's the case, no, those tanks are no longer in production.

 

[pecheux]

Re: Vented cap gas tank question:

OP....I'm wondering if your OMC motor is old, meaning your metal tank is one of the old pressurized tanks Evinrude/Johnson used for years waaaay back when. No vent but had dual fuel lines running to the tank. If that's the case, no, those tanks are no longer in production.

Nope ... and pehaps yes ... lol It came with a 1981 Johnson 9.9 bought new. It's single line and there is absolutly NO vent and I run it with the cap thightly closed. Under the sun there is pressure building up, when it cools off I dont realy know what happens ... lol Think I was once been told the cap automaticaly vents out when there is too much pressure.

 

[JimS123]

Re: Vented cap gas tank question:

Want to use the old OMC tank with my other fishing boat on a trailer (avatar) I did NOT know those OMC metal tanks were still available ??? Are you sure ??

Replacement plastic tank I saw was at a Mercury dealer, labeled Qwicksilver, cost approx $ 60. for that kind of money and name I would have expected descent quality ???

I haven't looked at an OMC accessory catalog in years, but I would guess that they can still be bought. Regardless, Tempo does make metal tanks. They are a direct copy of the OMC ones.

The metal tanks are self venting. No need to keep the cap loose. Better not to!

 

[emoney]

Re: Vented cap gas tank question:

You probably get more water "with" your gas than could get in via rain thanks to Ethanol.....