How to make a simple fuel syphon with valve


If you need to transfer fuel from a barrel to a jerry can, or from either of those containers into a fuel tank, but you don’t have a fuel pump on hand because you’ve been waiting six months for the supplier to send it to you (I won’t name names), then you’re stuck using a syphon to transfer your fuel.


The simplest form of syphon consists of a rubber hose and your mouth. You insert one end of the rubber hose into a barrel of fuel and suck on the other end until you’ve got the fuel up near your lips. Next, you quickly remove the hose from your mouth and insert it into the jerry can opening. If the level of the fuel in the barrel is higher than the tip of the hose in the jerry can, gravity will pull the fuel in the hose down into the lower jerry can. As this fuel falls into the jerry can, the space it occupied in the hose needs to be filled which forces fuel to come up through the hose from the barrel.

The fuel will keep flowing until the level of fuel in the barrel is lower than the end of the hose in the jerry can (e.g. if you lift that end of the hose up, or if the level of fuel in the barrel drops far enough). It’s very common for fuel depot staff in developing countries to use their mouths in order to syphon fuel into jerry cans or vehicles in this way, but it’s not a healthy practice – doctors definitely do not recommend filling your mouth with fuel every once in a while, which happens frequently when syphoning fuel.

So, how to reduce this problem with very limited supplies available? A syphon with a valve is one partial solution: stick a valve on one end of your syphon hose, leave it in the open position, insert most of the hose into the fuel barrel, close the valve, then pull the hose until the valve end is below the level of fuel in the barrel. Point it into a jerry can, open the valve, and the fuel will start flowing. This works very well until the barrel becomes about 3/4 empty, at which point it’s a bit tough to get enough fuel in the hose to take advantage of gravity’s pull without any suction. So, if you don’t have a pumping mechanism then you still need to use your mouth once the fuel level becomes lower. Still, a syphon with valve reduces the amount of mouth-powered syphoning by about 75-80% which is a big improvement while waiting for a real fuel pump to arrive.

Testing with water from one barrel to another:


Three staff members in Lubutu impressed that this actually works:


Close-up of the syphon valve. Once we had created between the valve and hose a sufficiently airtight seal to establish that the syphon actually worked, we added a very short section of hose to the other side of the valve to insert into the jerry can or fuel tank, which reduced the potential for spillage:


What you need to make a simple valve-operated fuel syphon:

  1. 1.5-2 metres of PVC reinforced hose (if you’re forced to use a section of unreinforced hose, you may need to strap something on to it to prevent it from kinking)
  2. PhotoDiarist

  3. 1 ball valve with a connector diameter roughly the same as the hose
  4. PhotoDiarist

  5. 2 nipples (this is the official plumbing term!) with threading that matches that of the valve
  6. PhotoDiarist

  7. 2 screw/band hose clamps with diameter slightly larger than the hose
  8. PhotoDiarist

  9. 1 roll of teflon tape
  10. PhotoDiarist

Then put it all together:

  1. Cut a 10-15cm length from one end of the hose for the ‘pouring’ end
  2. Wind teflon tape several times around the threads on one of the nipples, then screw it into the end of the valve; do the same for the other nipple
  3. Slide one of the hose clamps loosely around one of the nipples
  4. Insert this nipple into the long length of hose; this may take a fair bit of force if you’ve chosen nearly equal diameters – twist the nipple clockwise as you push it in
  5. Once the hose is connected to the valve in this manner, slide the hose clamp into position a few millimetres from where the hose meets the valve, and tighten the clamp as much as you can using a flathead screwdriver
  6. Repeat steps 3-5 above for the short length of hose on the other side of the valve
  7. Test your new syphon with water; if the connection between hose and valve is not airtight, the water will simply fall back down into the water container as you lift the hose out.

Of course, as we put this together, I never mentioned to the guys that adding a plastic funnel to the long end of the hose would turn this contraption into a standard university beer bong