Marine: Boating, Sailing, PWC, GPS and Navigation - siphon gas

I have a 17' fish and ski with built in gas tank and i want to remove the bad gas from it, it has about a half tank in it now.
I tried to slide a hose down the fill opening but it never touched gas, is there a anti siphon device in the tank?

How can i drain or siphon the gas out.
thanks.

I remove a panel to expose the level indicator..
I remove the indicator and syphon from there.

hmmm, where is the idicator, i don't think i have one.
I was thinking of removing the hose after the priming bulb to the engine and draining from there.

Hey, wwc, what is the capacity of the fuel tank? If you have a fuel guage on your dashboard chances are pretty good that you have the electric level indicator that greg mentioned. It's usually located on the deepest part of your tank, and if the boat manufacturer had any clue, there would be a removable deckplate over it for access. You can identify it because it is circular and about 2-3inches in diameter and has several screws around the circumference, and a wire lead in the center that gives your dash fuel guage its reading. If you remove the screws and pull it out of the tank, you'll find a float that measures your fuel tank level by measuring resistance on a coiled wire on its hub. Pretty simple but pretty ingenious. You can then siphon the gunky gas out of that hole. Putting a hose down the fill is okay in theory, bu you never know where the end of the hose is, and usually it curls up above the fuel level. Now, if the fuel level indicator looks to be in good shape, you may replace it, tightening the screws equally as if it were a wheel, but my advice is to just toss the thing and buy a new one. They are less than $30. Well worth the peace of mind!

thanks alot