Plastic Gas Tanks

[Clint KY]

I recently got a new (to me) 25HP Evinrude and it came with a plastic gas tank. My old tank was steel so I did not have the problem I have now. I went out Monday for about 3 hours and when I got back to the ramp I noticed my plastic tank was all swollen up from being out in the sun. I released the pressure by loosening the cap but even with that it did not go back to its normal shape and size till I put it in the workshop and let it sit for a few hours.

1.) Is this normal? I know the EPA made them remove the little venting screw on the cans, but this thing was seriously bulged.
2.) Is there a way around this? I priced metal cans, even used, and they are outrageous.

 

[mirroman]

Seems like the norm for plastic tanks.
I had the same problem and it worried the devil out of me, I could just see it popping open and spilling fuel. So I went back to my old reliable metal tank with a vent and feel a bunch safer.

 

[HeavyHook]

I must be confused or doing something wrong myself. Ive been out a bunch and in direct heat never had my tank expand one bit. When running the motor you need the vent to be open so wouldnt that vent itself or does it keep pressure since its connected to the outboard?

I dont mean to jack your thread but maybe you guys know.

I keep the vent open 99% of the time because of the pressure that could happen... is this ok?

When fishing I run the motor for 15-20 minutes to a spot and then use a trolling motor for 4-5 hours. during this time I usually leave the motor trimmed up, gas line attached and vent open on tank. Before leaving I give a few pump to feel pressure and it starts up perfectly and Im out. Is this a good way to go about that?

 

[Johnny]

1.) Is this normal? - yes, if you do not vent the cap screw

2.) Is there a way around this? - yes, vent the cap screw

[2]3.) HeavyHook, yes, that is the correct way.

IMO, in our 90* or better hot sun, it will have more pressure in it than
you could ever imagine. Same as the 5 gallon plastic gas jugs.
The main culprit is AIR in the container. Air expands more than the liquid gasoline.
The more liquid, the less expansion - the more air, the more expansion.
The steel gas cans have the same expansion issues as the plastic, they just don't swell up.
But, they DO generate the same pressure until you loosen the cap. Simple physics.
There are several posts on this forum and other boating forums about the same issue.

** if you do not have the cap in the photo, someone has switched it - and should be replaced.

as I stated, this is just MY dos centavos.



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[Clint KY]

I keep the vent open 99% of the time because of the pressure that could happen... is this ok?

No vent screw -

2.) Is there a way around this? - yes, vent the cap screw


** if you do not have the cap in the photo, someone has switched it - and should be replaced..

Again - no vent screw. And I have looked at all the new tanks and none of them have vent screws anymore. I questioned OMC about getting a vented cap for my older metal can and was told that the EPA had banned vented cans, so they were not available any longer.

If you or anyone knows where to get such a cap I would appreciate it greatly. I keep checking yard sales hoping to find an older metal can with a vented cap, but no luck so far.

 

[hwew]

Here is some reading.

https://www.nmma.org/assets/cabinets/Cabinet55/NMMA%20Industry%20Service%20Announcement%20Portable%20Tanks%20JUN2012%20Final.pdf

 

[Johnny]

wow - my bad for not keeping up with the times. I have not had a reason
to look at new gas tanks - thus I did not know the change.

good find, HWEW !!

A quick search of the popular spots shows the tank is for sale, but not the cap.
Which seems STUPID to me as the plastic tanks can and DO rupture from being
over pressurized.

I can vouch for this personally !!! 3 years ago, I filled my tank with 6 gallons of
gas, 5 mile ride to the lake . . . when I got to the lake, to my horror, the tank seam
had split and I had 3 gallons of raw gasoline splashing around in the bottom of the boat.
Two Game Wardens were at the landing and I went to them for help. They said I must
vacate the landing as not to possibly contaminate the water. I put the boat plug in before
I left the house, so the gas was not leaking from the boat. what a mess.
One warden loaned me a 5 gallon bucket to pour as much water into the boat as I could
(about 4 trips - 20 gallons) and empty my 2 powder extinguishers into the water and go
back home...... no fire dept. - no nothing..... what a mess.
so I can tell you the old sun baked tanks CAN and DO rupture . . .

I guess the EPA wins again ??? the old tanks are "BANNED" from use ?
meaning, if we just bought a new one 3 years ago, it must be scrapped to the recycle bin ?
oh no

 

[WaterWaif]

I am refraining from adding a tire stem with the valve removed to vent.
I leave the cap just loose enough that when temps cool in the evening a drawn out whooooo can be heard as outside air enters..
The option is the tank bloating like a road hit.

 

[riverbud55]

got vents in my new tanks I got with my ''14'' 25hp e tec and ''12'' tohatsu 6hp

https://shop.evinrude.com/product/343543/767525/_/Replacement_Cap_%28POP%29

 

[turbotodd]

Seen a few Atwood tanks break open. And a few no-name cheapie tanks (like the ones you get at wal mart and the like). They're all low-perm tanks, but all of the ones you get other than OEM ones (and even some of the OEM tanks) are cheap material and cheaply made. At 5 psi and you have a large 6 gal tank, there is a lot of square inches...so the actual pressure on the tank itself is pretty substantial. I think I was told something like 400+ lbs of pressure (not psi...it was measured pounds per square inch times the actual number of square inches).

What I do know is that the Yamaha OEM tanks are MUCH higher quality. They don't swell nearly as much-if any. Mine doesn't, and it's one of the first low-perm 3 gal tanks from I think around 2009-ish. Also the fuel lines that they sell are top notch. I've had mine since about the same time when I got the tank. Still very pliable, flexible, the bulb works excellent, it has set outside in the rain, under pine trees, inside, had gas all over and in it (old gas too)...all of which would make one of the cheapie lines become hardened up to the point where you can't squeeze the bulb. And in some cases, the line itself would just crumble or break or crack. Them Yamaha tanks and lines are NOT cheap! But...in this case, you get what you pay for, at least in my opinion.

Haven't seen or messed with a Merc branded tank...or Bombardier (evinrude), or tohatsu...or even suzuki. Just some of the aftermarket wal-mart and Academy tanks and the Yamaha's. The 6 gal Yamaha will swell a little but NOTHING like the Atwood tank I had, which would look like a basketball in about 30 minutes of sitting out in the hot sun we have here. Speaking of which, I was out on the water last week....I was done by 10am. Back at the ramp, I found my infared temp gun that I lost (must have set it in the boat while in the garage), and "shot" the boat's floor, which is painted OD .125 diamond plate. 163°. Figure by noon or or a little after, it'd have been closer to 175°. I do know that this time of year if you stay out all day, and walk on the floor with shoes on, if you stay in one place very long the soles of my shoes will melt a little, and stick to the floor. Pain to clean too. GF got mad because her flip-flops kind of melted a little. I need to do something about it...just haven't decided what yet.

 

[mirroman]

I have two plastic tanks and neither have vents, only my much older metal tank that I use now. I believe that here in Calif tanks with vents have been banned.

 

[onthewater102]

I've got a buddy who is always looking at my swollen tank and saying I need to punch a vent in it...apparently this isn't wrong but it is certainly disconcerting to look at.

 

[RiverBottomOutdoors]

How does it work if the tank is not vented? I don't get it.... I know that if you run a boat with the vent on the tank closed, it will lose fuel pressure.

 

[HeavyHook]

How does it work if the tank is not vented? I don't get it.... I know that if you run a boat with the vent on the tank closed, it will lose fuel pressure.

This is what I mentioned earlier and am still confused. Somehow there has to be a vent...

 

[onthewater102]

The o-ring pressure seal on the cap just gives out and sprays gas all over...good job EPA

 

[RiverBottomOutdoors]

https://www.boatus.com/magazine/2014/december/reports-new-epa-compliant-portable-gas-tanks.asp

https://www.youtube.com/watch?v=6kPCqCxipPQ

 

[Johnny]

DISCLAIMER: This may or may not conform to the EPA laws. Use your own discretion.

https://www.youtube.com/watch?v=lWAnMrSjelk

https://www.ebay.com/itm/5-Yellow-Fuel-Gas-Can-Jug-Vent-Cap-Blitz-Wedco-Scepter-Essence-Midwest-Eagle-/281247465570

auto type valve stem: https://www.youtube.com/watch?v=F6WZ9FrXPiE

Just remove the valve stem and adjust the black plastic cap to equalize internal pressure.






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[onthewater102]

Dunno about using the rubber valve stem around ethanol laced gasoline, probably work for a while but then start flaking off crap into the gas.

 

[Stump Bumper]

Dunno about using the rubber valve stem around ethanol laced gasoline, probably work for a while but then start flaking off crap into the gas.

Every boat owner should be avoiding ethanol gasoline at all cost. It is horrible for your boat motor, gas tank and fuel line. Last fall, after taking my boat out the first time in about 3 months, the motor would stall out every time I started to open the throttle. Upon getting home and disconnecting the fuel lines, I had this yellow gunk falling out. The culprit was the ethanol mixture in the high octane gas I was using. If you watch the video you will see exactly what I saw. I didn't mean to high jack the thread but this stuff is nasty unless you're running your boat as often as you run your car, then it's just bad.

https://www.youtube.com/watch?v=3pMFobZXZww

 

[mirroman]

And the EPA said it is going to increase ethanol content to either 15% or 20% to 'save the planet'.