Advice / Tips for Draining Old gas and checking fuel lines.

[Steve51]

Long Question – short answer…

I have recently installed a brand new engine and as such I have replaced all the fuel lines and filter etc. to accommodate the larger diameter fuel feed.

I also have about 40 gallons of stabilised fuel (gasoline) in my fuel tank that has been sitting for about 2 years.

Now I need to do two things … firstly I need to check the new fuel lines from the filter to the tank against leaks etc. and also need to check the condition of the old fuel.

Therefore it would be easier to draw the fuel from the tank from the new filter. I have tried a simple hand transfer pump and a bulb fuel line but that didn’t work.

So .. Just thinking of using an Edlebrock self priming 12v electric fuel pump for carburetors to undertake this.

Bearing in mind there is no fuel in the fuel lines at the moment, so will this work?

I initially wanted to draw a couple of gallons first just to check the condition of the fuel; I can even rig up a sort of fuel polishing setup with extra filter etc. if needed.

Thank you.

 

[Scott Danforth]

Your 2 year old stuff is no longer fuel

Pump it out, clean the tank, get fresh fuel

 

[airshot]

Years back I bought a small 12v fuel pump from Amazon just for pumping out tanks. Quite small, comes with intake filter, just add some 5/16" ID fuel line. I use a 8' long wire with battery clips to keep any spark at a distance. I think the whole project was less than 25 bucks. Just stick one end into the tank and the other into a 5 gal can. Go about your business then come back and replace the 5 gallon can. I never use gas more than one year old if it has been treated. You can add a few gallons at a time to your road vehicle to use it up. Treated fuel is good for one year, but becomes a big gamble after that.

 

[racerone]

Check your insurance policy.----Myself i would not risk trying to salvage old fuel.

 

[Steve51]

Thank you for your responses.

I had resigned myself to remove the old fuel but I did initially wanted to check if it could have been used in an old car at say 10% mixed with fresh.

My main concern was removing via the new filter thereby checking the new copper fuel lines back to the tank and the shut-off valve.

My initial attempt with a hand pump just didn’t work.

 

[airshot]

It will take forever with a hand pump, a small electric pump will make it much easier. Old fuel can be used in a small ratio with fresh fuel but you need to ask yourself, is it really worth it ?

 

[Scott Danforth]

but I did initially wanted to check if it could have been used in an old car at say 10% mixed with fresh.

It quit being fuel at least a year ago. Gasoline lasts 12 months from date of refinement

Now it's not even good enough to start a brush fire

 

[Scott06]

Thank you for your responses.

I had resigned myself to remove the old fuel but I did initially wanted to check if it could have been used in an old car at say 10% mixed with fresh.

My main concern was removing via the new filter thereby checking the new copper fuel lines back to the tank and the shut-off valve.

My initial attempt with a hand pump just didn’t work.

I’ll play the other side of the fence , have you taken a sample of the fuel out and seen what it looks like first. I have seen stabilized fuel older than that be fine. Have also siphoned fuel out of rusty fuel tank, let it settle in 5 gal buckets, siphon off the sediment and run it through a paint filter and used most of it .

 

[Bondo]

I’ll play the other side of the fence , have you taken a sample of the fuel out and seen what it looks like first. I have seen stabilized fuel older than that be fine. Have also siphoned fuel out of rusty fuel tank, let it settle in 5 gal buckets, siphon off the sediment and run it through a paint filter and used most of it .

Ayuh,..... I use the smell test,..... if it smells like gasoline, it'll run just fine,...

 

[Scott06]

Ayuh,..... I use the smell test,..... if it smells like gasoline, it'll run just fine,...

agreed seen was not meant literally.

I think the oldest gas I ran was about 8-10 years old, and this is E10, was stabilized originally but car just sat as an unfinished product for years.
Conversely this summer my buddies boat fuel smelled fine but got milky when sitting in a jar. Something in the fuel was screwing up the carb every two years. Rebuilt it once and almost got through two summers before it ran like chit again.

 

[airshot]

Where the gas was purchased originally can make all the difference.

 

[muc]

The biggest mistake I see when a DIY tries to drain their fuel tank. They try to suck it out with the existing fuel lines. This results in failure. The problem is that the tube that goes into the tank stops about 1" from the bottom so they don't get all the fuel, and what they leave in the the tank is the nasty stuff -- water, dirt and any phase separated fuel. Then the next time they use the boat, the motion of the boat causes all those nasties to mix with the new fuel = fail.
The best way to drain a tank.
Get the boat so it's leaning to one side (put a chunk of 2X4 wood under one tire), raise the bow so the front of the tank is higher and remove the sending unit. Note: now is the time to consider replacing the sending unit. Now take some soft copper tube (3/8" o.d. works good) and bend it so it will go to the lowest corner of the tank and pump or siphon it ALL out.
The second biggest mistake I see is people who think they can filter the crap out. Do a deep dive on fuel filtration to see why this almost always fails.

 

[Scott Danforth]

I usually pull the fuel sender as @muc suggests. I have a small section of aluminum tube (3/8" fuel line from a hotrod project) on the end of a hose going to a manual squeeze ball pump to get most out.

it also allows you to hose down the tank with simple green to clean it if you need to.

on really bad fuel tanks, you may need to use hot-water and simple green a few times, then a round of 96% isopropyl alcohol to remove the water

do not try to use a shop vac to suck fuel out of the bottom of a fuel tank out the sender hole......not unless you want to meet jesus. I believe there was a post on iboats about 10-15 years ago.