Running breather hose

[goona]

Gday all,

Need some advice on running a under floor breather hose to a new fuel tank I am installing. I wish to connect to the exisiting tank breather by way of a "T" piece to keep a neat finish but in order to do this I will have to run the new breather hose below the kill tank which will be below the fuel tank but it then goes back up under the gunwale and hence above the under floor fuel tank. (Hope that makes sense). My question is will this still work or will in the off chance fuel get into the line and cause a "lock" thus not allowing any fuel to flow to the motor or will it simply get sucked back into the fuel tank as it draws from the breather?

Thanks Goona

[goona]

Gday all,

Need some advice on running a under floor breather hose to a new fuel tank I am installing. I wish to connect to the exisiting tank breather by way of a "T" piece to keep a neat finish but in order to do this I will have to run the new breather hose below the kill tank which will be below the fuel tank but it then goes back up under the gunwale and hence above the under floor fuel tank. (Hope that makes sense). My question is will this still work or will in the off chance fuel get into the line and cause a "lock" thus not allowing any fuel to flow to the motor or will it simply get sucked back into the fuel tank as it draws from the breather?

Thanks Goona

[Noelm]

it is asking for trouble to have a low "loop" in a breather, it needs to be kept clear at all times, a low point will eventualy fill with fuel and will cause all sorts of problems later on, from blowing back when filling, to very slow filling, to even a possible fuel supply issue.

[Out-Station]

Goona, fuel from normal motion will overflow from the tank and collect in the low spot in the breather line. When your fuel volume expands it will be inclined to blow some of this quantity collected in the the line out the the breather, like noelm said, will make for very messy fill ups and some fuel loss when in use. Other thing is make sure you put your breather point on the stern away from any natural spray areas. I had a boat with a breather about half way along its side once, up high, used to suck spray in as the fuel moved around in the tank, used to get water in fuel issues till i isolated the problem.

Scott

[PADDLES]

g'day goona, like has been said, try not to have any low points in your breathers that form a "trap"

[cormorant]

My opinion is that it won't lock as lets face it a motors fuel pump will pull fuel through 20 foot of fuel hose so a 20cm dip full of fuel in a breather hose will not stop it drawing air through that fuel in the pipe. Preference is to have a loop up underside your gunnel rather than a low under a kill tank.

In all fuel breathers I have set up we use a double loop under the gunnel and they are often charged as it stops volitiles bubbling out as fuel expands and slows air coming in with temp changes.

If you have a "fuel spill" on fill up or in rough conditions a solution apart from fuel loops is to have a 6 inch of larger internal Diameter pipe in a vertical position as pipe goes up to the breather. It's increased internal volume will store and then drain back any fuel / froth that can bubble up. There is products on the market manufactured to do the same thing on larger boats. Do a google When filling lets face it that 99% of vapour comes out the filler hole as it is the point of least resistance and the people who have fuel breather filling issues have a problem with only a single breather point on the tank and often on a trailer it is not at the correct point in the tank or well designed

Have your fuel hose rise to tight under the gunnel so if you dip the side of the gunnel in rocking and rolling in it is less likely water will get forced up

Oh well there is a contrary view for ya.

Ask the manufacturer of your hull especially if the hold you are using was a option from original for another tank.

If people who made tanks would just put a open pipe in the top of the tank roof on the inside that ran diagonally from front to back then the tank on a trailer at teh servo wouldýt force fuel out a breather if the boat was tilted . $2 in production but a pain to retrofit as no room to do externally

[Lucky_Phill]

I have done a similar loop ( one ) as cormorant.

I had many overflow issues while filling tank and this ended up being the solution. I made the breather a large ( 30mm ) diameter hose with one large loop. It does collect a little fuel in the ' dip ', but to date has not caused a spill, splash or fuel feed problems.

maybe each case is different ???

My other issue is manufacturer design fault. The filler cap is at the stern of the boat ( on top of gunel ) and therefore when boat is sitting on trailer, it leans back and thus making filling an issue. What happens is the tank fills towards the breather outlet, instead of the inlet. Noble ( when they took over ) fixed this by having the breather outlet placed at the front of the fuel tank.

Be careful where you position the breather nozzle. making sure is does not face forward or towards the stern ( if on the transom ).... this allows ' mist ' to get into the tube creating small water droplets in the fuel tank. But, if you got a good fuel filter with water trap, this will not be an issue.


cheers
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