Re: How to pump old fuel out of built-in fuel tank
Depending on the size of the tank you could be leaving a quantity of water/fuel/muck in there as the fuel pickup is raised off the bottom of the tank.
Depending on the size of the craft, if it is trailerable or not, I jack and block the trailer such that the fuel tank is angled, the fuel pick up is on the lowered corner. Rig the boat trailer like this then let it set a couple of days, give it time for any water to completely settle.
If/when the tank is low enough on fuel, I remove the fuel pickup completely and stick in my own hose, all the way to the bottom corner of the tank.
This way I can be sure that I remove ALL the water and crud from the tank.
We can pull out water from under the fuel without draining good fuel.