Intex Pump Mods

It’s a bit of a rainy day here today, so I thought that I would use this time to post the modifications that I made to the Intex pump that I had purchased specifically for use with my ultra-light kayak.

I had already shown how I modified the adapter, that came with the ultra-light kayak, to the pump in an earlier post. However, I didn’t like the way that the pump was operating, so I took it apart to see what the problem might be. After inspecting the inside of the pump, I determined that the diameter of the ‘O’ ring on the plunger was too small for a good seal against the inside of the pump walls. This meant that a lot of air was escaping past the ‘O’ ring as I pumped, and this was decreasing the efficiency of the pump.

It would be a difficult task to find another ‘O’ ring that was slightly larger than the one in the pump, so I had to come up with another solution for this problem.


Here is the pump I am referring to. There are three sizes of this pump, as far as I know, and I can’t say whether all three sizes use exactly the same parts, but it would seem likely.


If you unscrew the cap off the end of the pump, and pull out the plunger, you will see this ‘O’ ring, in a groove, on the end of the plunger. Take this ‘O’ ring off.

Now, we will need to make another ‘O’ ring which is just slightly larger than the one you took off.


You will need some small diameter plastic tubing, like this. I happened to have some of this on hand, but it can be found in automotive stores. It might be used for windshield washer tubing, or I’ve also seen it used as overflow tubing on smaller batteries. It is probably sold by the foot, so I’m guessing that one foot would cost less than a dollar. The actual diameter of this hose is 7/32″ outside diameter. It must be this size, and I do believe that this is a standard size, so it shouldn’t be hard to find.

The reason I say that it must be this size is that it has to, not only fit in the groove on the plunger, but, it can’t fit in that groove tightly. There must be a bit of a gap left in that groove so that air can pass by the ‘O’ ring, and up the shaft of the plunger. This is what provides the ‘double action’ of the pump. The pump pumps air on the down stroke and the up stroke, and this ‘O’ ring is pushed back and forth in that groove on the plunger, in order to achieve this ‘double action’.

So, now that we have our plastic hose, we will need something to join it together with, so as to make an ‘O’ ring from it.


This is a 3/4″ piece of ordinary electrical wire. I believe it is about 12ga., but I’m not sure. The only requirement is that this wire fits inside the plastic tubing quite snug, so that it doesn’t pull off too easily.

Using the end of the plunger to guesstimate, cut some plastic tubing about the size you feel will be slightly larger than the original ‘O’ ring. It doesn’t have to be exact, but it should be larger than you think, rather than smaller. You can nip a bit of tubing off, if it’s too large, but you can’t add more, if it’s too small.


Now, stick the 3/4″ piece of electrical wire about half way into one end of the tubing. Then, wrap the tubing around the inside of the groove on the end of the plunger, and join the tubing by sticking the other end of the electrical wire into the tubing.


Put some Vaseline on the end of the plunger for lubrication, and see if it fits inside the pump now. It should fit nice and snug, but not so snug that you have trouble getting it in there. If it seems like the ‘O’ ring is too large, you can take it off and nip a piece of the tubing off, and try it again. I was lucky, I got mine right on the first try.


Here you can see the original ‘O’ ring on the left, beside the one I made, on the right, which is slightly larger than the original.

If this procedure is done correctly, you will now notice a bit more pressure, when you pump. This is because more air is being pumped, and less is leaking past the ‘O’ ring. You now have a more efficient pump.


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