Questions about Fuel Tank for boat

I'm looking at getting a new fuel tank for my boat. One that will fit in the area between the transom and rear bench seat. With that being said I need a small profile tank. All the tanks I have been looking at are low permeation tanks that do not vent. I thought tanks needed to vent so that the outboard would run properly. I have a 79 Johnson that is on a vented tank. Are these new tanks better?

I have a 3 gallon tank right where you are looking to put yours. It fits in there perfectly. I don't have a new tank, so I'm unsure how they vent. I'd be hard pressed to believe that they don't vent. If they don't just crack the fill cap a turn or 2.

[url=https://www.tinboats.net/forum/viewtopic.php?p=347049#p347049 said:

muskiemike12 » Today, 11:17[/url]"]I have a 3 gallon tank right where you are looking to put yours. It fits in there perfectly. I don't have a new tank, so I'm unsure how they vent. I'd be hard pressed to believe that they don't vent. If they don't just crack the fill cap a turn or 2.

Click to expand...

Thank you for answer...opening the lid a little would work.

What understand is the cap will let air in but won't let vapors escape. Some people have replaced the cap with and older one when they had issues.

Every portable fuel tank for outboards is vented;if it isn't you are looking at a portable transfer tank and is not made to hook up to an outboard.

The vent is designed to both let air in and let vapors escape. If you lock down your tank on a cool morning and it heats up during the day it will expand like a balloon ready to pop! Open the vent and it relieves itself! The better tanks will not allow liquid to escape through the vent; this is probably what lckstckn2smknbrls meant.

If you crack the fuel cap you run the risk of spilling liquid fuel into your boat; never a good idea.

Bass Pro sells a 3 gallon tank that fits perfect back there.
https://www.basspro.com/Moeller-Marine-Products-360-Series-Portable-Fuel-Tanks/product/10210684/

Some of the newer tanks have an automatic vent instead of the manual vent. They only vent when there is enough vacuum or pressure on the tank, depending on the conditions. I had a tank that blew up like a balloon and would not vent. Didn't care for that. The epa put the stop to the old manual vent because it let vapors escape all the time. I guess the little 3 gallon tanks put a hole in the ozone or something.