I have a FULL tank of 8 month old gas in the boat and was gonna burn it in my cars.I tried to siphon it out through the pick-up tube but,it has so much restriction that it wont siphon.If I hold the siphon tube UP with about 3 feet of fuel in it,it doesn't flow back to the tank either.Is there a back flow valve built into that pick-up tube(96 bayliner cierra express)and,shouldn't it be pretty free flowing?Can't imagine the fuel pump should have to suck THAT hard to get fuel. Jerry