Thanks Wilbo... and unknown originator of the photos.
One of the unconnected bits on our motor is shown in the first photo. At the bottom of the pic there is a cluster of three steel(?) pipes of various sizes. The one that has no hose on it is the one we are interested in. It is bent slightly downward at the end, suggesting that it probably heads rearwards and down. There is a similar sized steel outlet teed into the water line that runs around the block. This one is located more or less where the other (pictured) fitting is pointed. Simplest answer is that the two are linked, but is that the right answer? Also when I looked at the motor t'other day, I noticed a clip that would hold the flexible hose too. Clip was up under the manifold, and if you weren't looking for it you'd probably never see it.
Like petespipes I also haven't uploaded pix to here yet, but if I don't get my question across without them, I may have to learn. Not that keen as computer is horribly slow, but we'll see.