fuel burping!

[inveratta]

Previously I have never noticed or seen this ...but after an engine change from inboard to outboard the breather burps fuel as the day warms up.I was standing beside the boat when quite a spray of fuel pushed out and dribbled down the stern.

I understand this is from the expansion of fuel....when the original breather line was installed by a mechanic...he put a loop in the breather line... near the breather vent ..I cant check now because the boat is stored elsewhere..but is it possible that you can put the loop ..too close to the outlet....and is a loop really necessary...can you achieve the same thing by just fixing the breather line higher than the vent. ? This at least would get rid of the little storage pocket for fuel near the outlet.

[Fed]

Loop or rise it makes no difference, maybe you have a downwards loop which will hold some fuel.
114532

If the tank is full with the boat tilted up then you can get to a stage when the breather is submerged and the expansion will push the fuel out anyway.

[inveratta]

Loop or rise it makes no difference, maybe you have a downwards loop which will hold some fuel.
114532

If the tank is full with the boat tilted up then you can get to a stage when the breather is submerged and the expansion will push the fuel out anyway.



AH...Thank you......I guess that they have installed with a downward facing loop then...will check this weekend.

[Chris Tucker]

Coming soon to a boat near you (thanks to a global focus on emissions) will be fuel tanks designed to all but eliminate this issue. There are multiple ways to achieve the goal but you'll find most will result in a 5% reduction in the usable volume of fuel tanks (so there is space for the fuel to expand in the tank without overflow) and vent and fill fittings designed to prevent over filling and back flow.