Not true about the filament keeping water out of the system. I drained about a liter of water off the bottom of the tank through the reserve. Where did all that water come from you may ask? From not shifting to reserve every couple of tanks, even when you don't need to. This crap they call gas these days with the ethanol in it, brakes down over a short period of time. So if you don't use the reserve, the bottom of the tank will fill up with water and what ever other crap they put in gas these days. Not to mention the occasional bad gas station in ground tank. So don't find out the way I did. on the road and running low on gas, shifted to reserve and almost killed the engine. Good thing there was a gas station only a mile down the road.