View Full Version : How to siphon out old gas?

09-29-2006, 11:58 AM
Hi all,

I have an 87 GN that's been in storage for several years which won't start. I believe this is because the gas is old, although I suppose it could be due to various other reasons. Anyway I purchased a cheap manual pump to siphon the gas out of the tank, but it's not working for me. I can only insert the siphon tube so far down the neck before it gets stuck on something. Anyone know why this is or an easier way to remove the old gas. I'd rather not have to resort to removing the entire gas tank to empty the tank. My goal is to remove a small amount and put it in my lawn mower to see if the mower will run on it. If it does, then I can assume that the gas is not the problem and I can start to look elsewhere.


09-29-2006, 01:31 PM
Take the cap and schrader valve off of the fuel rail and attach a long hose. Apply 12v to the test lead located behind the alternator which will activate the pump. Put the other end of the hose into a suitable container and pump the fuel into the container.

09-29-2006, 02:50 PM
Two questions:
1 - what size diameter hose are we talking?
2 - how exactly do I apply 12v to the lead? Connect a wire from the positive terminal of the car batter to the lead?

09-29-2006, 07:52 PM
1. I don't know the size, but since it isn't under pressure, just clamp a rubber hose over it. Or, maybe someone who knows will join in.
2. Yes, run a wire from the battery.

09-29-2006, 10:33 PM
Any hose that will fit over the shrader valve on the fuel rail - 3/8" will work. 12V from the battery or the back of the alternator to the single wire black connector fuel primer/test lead mentioned.

09-30-2006, 10:54 AM
I'll try to take pics to do up a tech page of this this week. Not sure why no one has. The hose size *might* need to be 5/16 to slip over the end of the fuel rail. (where the schrader valve is removed in the procedure, not "the schrader valve")

09-30-2006, 11:45 AM
Thanks Keller. Technically one needs to first place a rag under the fuel rail end where the shrader valve is, unscrew the shrader valve cap, release any existing fuel/pressure by depressing the spring/pin assembly in the shrader valve, and then remove the schrader valve core (made of spring, pin, and seal) from the shrader valve with a removal tool and then push the hose over the fuel rail end where the threads are for the cap. I'll try to be more careful with my words in the future. It seemed like the open questions were hose diameter and where to get the power source. Thanks.

09-30-2006, 06:48 PM
It is 3/8" hose, and it might as well be "fuel line" rated hose.

10-02-2006, 12:22 PM
Thanks for the help guys! :-)

10-06-2006, 09:59 PM
I had the same problem. When I hit that same thing you're talking about, I spun the hose as I pushed it into the tank. The end of the hose had a slight bend on it which flipped over that "wall" when turned. I drained 10 gallons of 10 months of stale gas out.