I have a question.


My current O/D sport jet (called JayLow, as it's a low wing version of the JayTee in my avatar) is powered by a Jets-Munt VT80 and is fitted with a DuBro fuel tank (80 oz or 1.8 litre I think).
PROBLEM I seem to have fuel seepage from the vent, judging by the evidence on the bottom on that side (port). Also, I have noticed that when I do a slow roll, or an inverted segment, there seems to be a whiff of fuel, a white streak maybe six to ten feet long, coming from the model. I don't always notice it, but maybe it is always there. If it is travelling 190 to 200 ft/sec we are talking about a fraction of a second, 1/20th or so.
I always imagined that once the engine was running, especially at high power setting when I'm doing rolls, it must be sucking air all the time and so no fuel could be ejected.
QUESTION What could cause a brief ejection of fuel when inverted? And what is the cure?
The Tygon vent line is unusually short. Would making it much longer, with a loop up to the tank top, be a solution?
Any ideas from all you clever experienced chaps out there?