Good. I was having a hard time figuring out how a repulsion start motor was running in reverse. I'd never seen one which was reversible. Apparently yours is but it requires changing the angle of the brushes.
The pics aren't clear enough to give me the detail needed to see exactly what type of adjustment there is. However there looks to be a screw or something just to the left of the sliding collar. That might be a lock for the adjustment. Here's a generic description of how the adjustment works so maybe you can figure it out. Nearly all industrial manual clutches will have a screw adjustment of some kind. The screw will be in the form of a ring which will have a lock of some kind. Some locks are simple spring loaded pins, others are metal tabs that fit in a slot and are bolted on. There are other styles out there but those two are the most common (the first is Twindisc style and the second Rockford). In this case with the small size of the clutch one of the alternate options for locking may of been used. At any rate there will be a ring which once unlocked can be screwed in tighter or out looser on the discs. There will be a lever system of some form which will go over center when fully engaged. Some use rollers over a cone which has a flat for the rollers (or sliders) to sit on allowing the clutch to stay engage (Twin Disc style). Others will have levers which are attached to the spider so that when the slider is all the way in the levers go over center (Larger Rockford and newer Twin Disc style). There are still other styles but I can't tell for sure in the pics which one this uses.
Based on your description of having trouble getting it disengaged the first time I'd say that the clutch it to tight (or you're simply scared to put enough force on the lever). It really should snap in and out with a reasonably sharp feel but not so hard that you have to really have to lean on the handle. However if it's adjusted to loose then it'll slip under heavy load.
There's no way that the clutch is throwing oil into the end of a copper tube. Actually from the looks of it I'd say it's a fairly common system. I bet if you look on the lid of the gear box you'll find some features on there that will cause oil slung up on the lid to run over and drip into the sheet metal tray with the copper tubes attached. That tray provides the source for the oil and gravity takes over from there. The tapered end oils the spindle bearing. The two copper tubes oil the input and throw out bearings.
Wayne Cook Shamrock, TX