I have a two line system on my two gas engined models which have performed flawlessly during several hours of operation. One line is the vent which exits the bottom of the model, while the other, the feed line, uses a standard clunk in the tank and a fuel dot grafted into it along with an inline filter just before the carb.

My gas pan uses a felt type chainsaw fllter on the pick up line, and a automotive type fllter in the feed line which fills the tank. Is this system okay or have I just been lucky so far.