Draining old fuel from under deck tank

[biggziff]

1988 Baretta bow rider and I need to drain about 1/2 a tank of old fuel. I tried to create a siphon (before I knew about the anti-siphon valve) and have tried to pressurize the tank via the vent, but cannot get the fuel out. I used a vacuum pump with a small reservoir and that works, but will take me a month to get the fuel out. Aside from using an electric fuel pump from a car fuel tank or some manual pump device or pulling the sender cover and putting some hose in there (probably won't get all the fuel) is there any other simple way to get the fuel out?

Also...is there any reason I wouldn't want to use a fuel primer bulb on an I/O boat like this to ensure that the fuel pump can get fuel after the boat has sat for a while?

thanks

 

[tpenfield]

Re: Draining old fuel from under deck tank

I usually attach the siphon hose to the fuel line that leads to the engine and then run the siphon tube out of the drain hole in the transom.

If you can position the boat in an elevated area, then you could siphon the fuel into 5 gallon cans positioned at a level lower than the boat. Otherwise you could pump it out using either manual or electric pump.

I pumped about 30 gallons out of my boat's tank last Fall with a manual pump . . . it took a while . . . maybe 20 minutes for each 5 gallon can.

BTW - don't pressurized the fuel tank to try to force the fuel out. Bad things can happen.

 

[biggziff]

Re: Draining old fuel from under deck tank

I usually attach the siphon hose to the fuel line that leads to the engine and then run the siphon tube out of the drain hole in the transom.

If you can position the boat in an elevated area, then you could siphon the fuel into 5 gallon cans positioned at a level lower than the boat. Otherwise you could pump it out using either manual or electric pump.

I pumped about 30 gallons out of my boat's tank last Fall with a manual pump . . . it took a while . . . maybe 20 minutes for each 5 gallon can.

BTW - don't pressurized the fuel tank to try to force the fuel out. Bad things can happen.

I did exactly what you suggested, but as the line has an anti-siphon valve in it and I don't know where it is to bypass it you cannot get it to siphon.

Pressurizing the tank (3-5 psi) was a recommended method from posts I read on here as it allows you to open the anti-siphon valve. Didn't work for me.

 

[tpenfield]

Re: Draining old fuel from under deck tank

Are you trying to siphon from the "filler tube" line (that you would normally use to fill the tank) or the line that runs to the engine?

 

[biggziff]

Re: Draining old fuel from under deck tank

Are you trying to siphon from the "filler tube" line (that you would normally use to fill the tank) or the line that runs to the engine?

The engine supply line (as you suggested above).

 

[NHGuy]

Re: Draining old fuel from under deck tank

If you can get to the top of the tank you can take out the anti siphon valve and replace it with a barbed fitting of the same thread. Put a hose on the barbed fitting and siphon from there. If the tank has gunk and crud in there you will need to take out the sender for a look anyway. You may need to use a brush on a stick to loosen any junk from the sides of the tank. Then shoot a little gas in there to float out the junk. The tank needs to be perfectly clean. If you aren't really sure it's clean get some extra filters, run the tank from full to empty a few times and change the filter repeatedly til you trust your tank.

 

[biggziff]

Re: Draining old fuel from under deck tank

If you can get to the top of the tank you can take out the anti siphon valve and replace it with a barbed fitting of the same thread. Put a hose on the barbed fitting and siphon from there. If the tank has gunk and crud in there you will need to take out the sender for a look anyway. You may need to use a brush on a stick to loosen any junk from the sides of the tank. Then shoot a little gas in there to float out the junk. The tank needs to be perfectly clean. If you aren't really sure it's clean get some extra filters, run the tank from full to empty a few times and change the filter repeatedly til you trust your tank.

Thanks...I'm not going to try to clean the tank as the fuel is coming out clear and without any debris, but it's old and discolored. I've bought 2 clear fuel filters already to keep an eye on what come out of the tank when it is sloshing around on the water instead of sitting quietly in my driveway.

I guess unless I can think of another way I'll just take an old electric fuel pump and get the job done. It's the last thing on my list before this boat can go in the water for the mechanical shakedown.

thanks