OK so now we see the culprit clearly. This is the passenger side of the tank. You can see the filler neck and, if you look closely, a bit of the fix I made.
Next, we move up the the top of the tank. We are going to take off the fuel pump access cover on the deck.
Take a 1/4 inch or 3/8 inch bit and drill off the caps of the cover. There are four. Becareful not to go through the panel. Just drill to knock off the head of the rivet. Once those are gone, remove the panel.
Holy carp it's dirty in there!. It's mostly dust that get shot up there as you drive. Wip it down a bit now to get the heavy stuff off. We will be removing the pump and sender and we dont want all the crap dropping in the tank.
Here is a place I vary from the shop manual. I remove the pump and sender. Two reasons. One, in the shop manual, they have you "notch" the top edge of the hole to let the pump fittings clear. If you simply remove it, the top of the tank is fairly flat and will come out easier and no extra cutting. Second, the big gaping hole lets me lift it there. Trust me, it will help and it's easier.
So taking out the pump and sender. The assembly is held in place with the big white perimeter nut. You will likely not get this out by simply twisting it by hand. Get a rubber mallet and a large screw driver or a large blunt punch. Then pick a notch and start tapping. It does not take a huge force. It will move 1/2" at a time. Be patient, be calm, it'll come off. Keep working the edge opposite the fuel line and electrical connetor so you don't hit them by mistake.
Once the nut is loose, remove the fuel line. It's a quick connect fitting. Simply press the side perpendicular to the locking pins and pull it off. That's a snap. You'll get a few drops of fuel. I wrap a couple of gloves over it with a piece of tape. It'll cat the drips. Remove the electrical connector. Then the nut will come off. Pull the sending unit out. As you are coming out with the unit, the sender float is still in there. You will need to tip the unit to let the bar clear. VERY IMPORTANT... the bottom acts as a built in sump (Very nice by the way!) but as you remove it and tip it, let the fuel drop into the tank. It's going to take a minute or so. Once the fuel is mostly out.... pull it out keep an eye on the sender float and bar. Place it someplace safe and on a rag so as to not damage it.
At this point I grabbed the Mytivac. It is an air operated fluid vacuum, basically. I pulled out the fuel left at the bottom. It was about three gallons. I put it into a gas tank to be used in the pressure cleaner.
Next.... you need to remove the filler neck hose at the tank. That's a clamp. Simple. As I mentioned above, there is a roll over valve in the filler neck on the tank. as you move the tank out, no need to worry too much about fuel coming out there. I shove a rag in there for small things, but it's not going to drop anything back out through the neck.
Once that's out we have three lines/fittings left to remove. I chose to remove one of those first. Truth is you can get them off as the tank comes out. Since I did not know, I chose to pull it off as it holds the strap down and I had the tool to do it. It is the vent line on the return fitting. It's on the passenger side. You can see it in the photo below. This is shot through the opening on the top deck.
To get that off I used this:
I reached in there with the pliers, squeezed the quick connect latch and off it comes.