Breathers on fule tanks.

[JEWIENEWIE]

I have noticed that over the last few hot weeks, my plastic fuel tank expands so much i am suprised that she hasnt blown or split. Is it a bad idea to leave the breather open or is there a chance that water may enter the breather and containamait the fuel.
Jewie

[finga]

If the tank is fairly protected from the elements leave the breather open just a smidge.

[Marlin_Mike]

What he said. The expansion is form the fumes.....give thm a small gap in the rbeather and hey presto, no more expansion. Just keep it clear of the weather

Mike

[JEWIENEWIE]

So it is possible for water to enter through the beather if it is left open.
Jewie

[Marlin_Mike]

Give the water a poo**teenth of a gap and it will get it.

If your tank is in the open where water might get in, here's a little tip.

Cut a plastic 2 litre coke bottle in half. Open the breather a touch, then sit the bottom half of the cut coke bottle over the fuel cap/breather. The water wont get in then.


Mike

[JEWIENEWIE]

Cheap, simple answer thanks mate, not rocket science is it.
Jewie::)

[majed1965]

Closed breathers cause problems with engine performance when running. Its best to keep open at all times.

[Kerry]

....Closed breathers cause problems with engine performance when running.

Nah closed breather can not cause problems with engine performance when running

'cause the engine won't be running if the breather is closed, period.

As for the tank expanding etc with the breather closed then is the fuel tank up to scratch or some cheap thin plastic model? If you can't completely close the breather when no in use due to possibly blowing/splitting the thing then sounds time to toss it out!

[majed1965]

I just bought a boat last weekend and took it it for the first time on Monday. It ran well for a few minutes but then seemed like it wasnt taking fuel properly. The tank i was using does not have a breather as the cap is fully enclosed with no hole and the other opening is the hose connector. It looks like a quality plastic tank but defintely no breather. Will test out this weekend if it runs better with a breather cap. Will let you know. (i'm hoping its a breather issue and nothing more serious)

[Kerry]

The vent might be built into the connector? But without being vented the engine will simply stop, no go!

[Gary Fooks]

Water will get in anyway

you need the breather open when running so air gets in to replace the fuel burned

This air then cools overnight and you get condensation inside the tank


When we check the fuel tanks every morning on light aircraft there is always a few drops of water that is drained off.

Gary

[seatime]

I prefer to close the breather (filler cap style) on portable plastic tanks when not being used, and always kept them in the shade.
the Quicksilver 25 lt tank can expand to look like a watermelon, and contract and look like a prune, but hasn't split or leaked, or suffered from condensation. maybe keeps the fuel fresher for longer too?

forgot to open the breather once, after a couple of minutes the motor started spluttering, the tank was like a prune, I opened the breather before it stopped, and got going again. you usually only do these things once!

[JEWIENEWIE]

My tank is the same make gelsec and yes the thing looked like a balloon the other arvo. I am suprised that a fuel tank can expand and contract and not split or blow.
Jewie

[rick k]

My OMC factory fuel tub does the footy thing when hot, and has no breather that I can see to let air in. Must be one there somewhere.....