How Do I Drain The Onboard Fuel Tank?

[manitoulinman]

Any suggestions on how to drain a fuel tank safely? I have a boat with three years (or older) fuel mixture in it. I need an efficient way to drain the tank. It is aluminum and it feeds from the top of the tank. I don't think gravity/siphon will work. Any ideas would be appreciated. Thanks!

 

[drewpster]

Re: How Do I Drain The Onboard Fuel Tank?

I have an old universal 12 volt electric fuel pump I bought at a parts store years ago. I think I picked it up for around $11 back then. I use it to pump out old tanks. Try to pump the gas out from the lowest part of the tank. If you have a trailered boat, jack the trailer up in a way that will cause the gas to run to a convenient place in the tank and pump it out from there. You can also connect the pump directly to the fuel pickup fitting on the tank. However this will leave a little fuel in the bottom of the tank. I generally have better luck removing the fuel level sending unit and drawing fuel from there. I only go to that trouble if it is accessible and I want the tank completely dry.
Safety tip! Keep the pump and all its electrical connections well away from the tank you are pumping out. A small arch while connecting the pump to the battery is enough to ignite fuel vapor. Always connect hot first then ground in that order to minimize arching. In fact it is safer to make permanent connections at the pump wire and at the battery and use an inline switch to turn the pump on. Never rig bare wire connections when using electric pumps that pump fuel!
A decent electric pump can lift fuel a few feet and drop into a gas can over the transom or over the side. I use the old gas to run in my lawn mower if it does not contain too much water. You can get rid of the old gas at a recycling station that takes used oil. Never dump it in your yard! It will kill your grass and end up in our waterways.

 

[lowkee]

Re: How Do I Drain The Onboard Fuel Tank?

It takes a while, but I used a hand utility pump (usually bright orange, looks like a tiny bilge pump) to pump the remaining 15 gallons from my tank. Finding a new home for the gas was the tough part.

 

[Utahboatnut]

Re: How Do I Drain The Onboard Fuel Tank?

You might be abel to siphon it with the proper hose placement maybe run a small (it will take a while but) hose through the bilge drain and siphon through that way. Pull the gas line off the engine and seeif you can extend it and get a siphon going that way. Make some kind of a plug to go ontofill neck, temp. block vent line and put a few lbs pressure in the tank and it will run out the fuel line to the engine. Find an old electric fuel pump and connect lines to it and pump it out that way. Don't use anything that isn't made for gas or flammable liquid transfer. take the fuel sending unit out and siphon or pump through that way. I would put some seafoam or the like in it once you are done draining it just to let it help with any water etc that will be left in there you will never get all of the gas out.

 

[erikgreen]

Re: How Do I Drain The Onboard Fuel Tank?

Last time I did this I used a rotary pump meant for a 55 gal fuel drum with adapters to make the hoses fit, and I connected it to the fuel outlet in the tank after removing the hose that went to my fuel filter.

I'd recommend picking up a fuel transfer pump or any small electric pump that's ok'ed for gasoline use from a tools or farm supply place, or barring that any hand pump that's ok for gas use.

Keep a fire extinguisher handy at all times, and work where you have ventilation so fumes don't build to the point where they can go boom.

Ditto on the comment on finding places for fuel to go. I borrowed four 5 gallon plastic cans last time and bought two more, and it was still barely enough. Keep the gas for running your lawn mower or something once you filter it.

Final safety note: An empty tank can be quite a bit more dangerous than a full one... it will fill with fumes quickly, and a spark will then make it explode. Even a tank with the cap off will fill with vapor because gas fumes are heavier than air. Make sure you take precautions.

Erik

 

[Bedrest2]

Re: How Do I Drain The Onboard Fuel Tank?

On my boat I left the fill cap tight, pulled the line from the fuel pump and put in a bucket, tightened a blow off from air compressor to the vent line and slowly
added pressure, not to much, you want to get the gas out not blow the tank
walls, when the bucket is full enough to handle pull the blow off out of the vent line and air will escape there.
Pump line is siphoning near the bottom of the tank, to help raise the front of the boat.
Hope this helps, remember about the fumes.
Good luck, worked for me.

 

[coolguy147]

Re: How Do I Drain The Onboard Fuel Tank?

well u can get a hand pump thats pretty long and pump untill the fuel reaches the pump. then it will automatically siphon out. i have this one thing that i use. porbably can buy from the store

 

[manitoulinman]

Re: How Do I Drain The Onboard Fuel Tank?

Thank you all for your advice...I will keep you updated on my results! Great Membership!!! Thanks again!!

Bill

 

[109jb]

Re: How Do I Drain The Onboard Fuel Tank?

Don't use a wet vac. Very dangerous.

Siphon will work. It makes no difference in the hose routing as long as the free end of the hose is lower than the bottom of the tank. If the boat is on a trailer then no problem. I just drained mine on my outboard powered boat by cutting the hose at the engine and adding more hose with enough length to go down the outside of the transom to 5 gallon cans. In the case of an outboard there is a pumo siphon bulb that I left in the hose from tank to 5 gallon can. I simply placed the free end into the 5 gallon can and pumped the bulb until fuel started flowing and it siphoned from there. If you have an I/O that doesn't have a bulb, you can buy one at Wal-mart or any marine store for just a few dollars. When the 5 gallon can gets full, just pinch the hose with a pair of vise grips to stop it so you can put another can under it.

 

[J. Mark]

Re: How Do I Drain The Onboard Fuel Tank?

I second the advice to not use a wet vac- the potential for explosion is simply too high.

As to using air pressure through the vent line . . . Tanks are pressure tested, but at a very low pressure level (Like 3 PSI or 20 KPA if you prefer)

I'd be very leery of that method, though I won't go as far as to say it is clearly a bad idea-just that it wouldn't be my choice for an inexperienced person to try the first time.

 

[Thajeffski]

Re: How Do I Drain The Onboard Fuel Tank?

Dangerous suggestion deleted by a Mod

Wow, you're dumb.

Let's use a motor that's absolutely making sparks and run gas through it!! Great Idea buddy. I hope for you and your kids sake you think a little more the next time you have a problem to overcome.