Gas leak?

[Dan]

I'm looking for some opinions here. Here is the situation. I have an '88 23'cc. A couple of weeks ago, I topped off my 130 gal tank based on what my Navman fuel meter said I needed. This past weekend, I was doing a prefish boat check and noticed gas leaking out of my bilge drain. I proceeded to pull the aft deck panel out and discovered about 1.5 gal of gas in the bilge. I removed all of that gas and waited til the next morning to find more gas in the bilge. I did not notice any leaks around the sending unit, filler hose, or the vent hose thru the small area of the inspection plate. Thinking the worst I assumed I have a leak in the tank which will require the obvious tank removal. Yesterday evening, I was going to start by pumping the gas out of the tank by removing the sending unit and inserting a hose thru the hole on top of the tank. When I took the first screw out, gas shot up thru the hole about 6", so I immediately put the screw back. I then decided to go thru the 90o elbow that the filler hose was attached to. Gas started leaking out of that as soon as I started loosening the clamps. I then went thru the gas filler cap. You get the picture. The tank was FULL. Anyway, I proceeded to pump 50 gal out of the tank into a 55 gal drum and cleaned up all the gas that leaked into the bilge. I set the sending unit back in the tank and it still reads almost full. It should be reading a little less than 2/3. It has been more than 24 hrs and the bilge is bone dry. What do you guys think? I'm thinking the tank was overfilled and leaking out of the vent hose or the sending unit. I replaced the filler hose 2 years ago b/c it was dry rotted, but the vent hose, I assume, is original. And I do not remember the brand of gasket sealant I used on the sending unit, but I never was happy w/ it. I am going to continue to pump out all of the gas into drums to see out much I actually have. The Navman fuel meter may need to be calibrated. Sorry to be long winded. All opinoions are wanted.

Danny