1) You can either buy a way overpriced 914/6 washer pump OR

You go to your local porsche salvage yard and get a washer pump from a '70s 911 (which looks strikingly similar to the 914/6 pump)

2) Then, you mount it in the stock (914/6) location which is under the washer bottle.

3) Rip out all the washer hose that goes from the bottle to the steering column (careful, could still have water in it), but keep it, we'll need it later.

4) Remove the 2nd hose from the steering colum and fiddle it back into the cowl area through the front firewall. Take the hose and connect it to the outlet of the pump. (you may wish to trim it, it's too long)

5) Remove the hose from the spare tires and fiddle it through the firewall, throw it into the trash.

6) Take the hose from 3) and put one side back on the bottom of the bottle (special connector, don't brake it!), then cut the hose to length and connect to the input of the pump.

7) Take off the black bottle cap and drill a small hole into it, next to the valve stem (hole size about the dia. of the washer hose). This is needed because the cap has a pressure valve in it that won't allow air to get into the bottle. You need to bypass this, otherwise the pump will not be able to get much water out of the bottle.

8) 2 options for the wiring:

8a) Run 2 wires inside and mount a separate switch (push button style) either in the dash or the center console, and hook it up to 12V (through a fuse of your choice)

8b) If you have the intermittend wiper relay harness, you can also run the pump off that, just extend the brown/black wire (trigger from steering column) and use it as the 12V feed for the pump. This way, every time you pull the wiper lever towards you, you get the 4 run intermittend + fresh water! NOTE: The brown/black wire was NOT an option on early car, '72 and later, if i'm not mistaken ...

And now on to the pictures ....

PS: Just in case you wonder, YES, this stuff in the pics is sand.
I had the car cleaned inside out for the WCC, all you see is NEW since then. More than 1 year since the sandblasting and the crap is still seeping out!

First, the completed assembly

Next, the pump. This is the stock 914/6 location (more or less), black hose is intake from bottle, transparent hose is outlet to the nozzles

Next, the cap with the additional hole for breathing

Next, a splitter for the two nozzles

Next, the intermittend relay (well, i took mine out for AX), you can see the brown/black wire that comes from the steering colum. Split and extend this to the pump if you want to run the pump off the wiper lever

Next, backside of the nozzle, the arrow marks the approx. location where the brown/black wires comes out of the main harness

Next, the mighty fine nozzle itself

Next, the push style button in the center console

Voila, we have a washer!

And because i know the proof is in the pudding, err, the bottle in this case, i made a little video:
Washer - The Movie, a 914world.com exclusive
If it doesn't play, try right-clicking on it and select "Save target as ..."

That's it!