Just took mine off of my 2301 (should be the exact same as your 26) and the manual says the tank has to be less than half full. When I unscrewed it, the fuel line closed on its own. I had my tank nearly empty just in case it wanted to drain out on my driveway. Be careful putting it back in though, I assume there's some sort of ball valve that moves out of the way when the filter housing is pushed back into the filter base because I started turning mine the wrong way and fuel dumped out everywhere until I realized what I was doing and turned it the right way to tighten.
