Should be a single plate clutch, but it is the same type as a "twin disc", Rockford etc clutch. The lever snaps the linkage over center so it holds pressure on the clutch disk without you holding the lever until you snap it back out again.
Open up the clutch cover put transmission in neutral and rotate it until you see the lock button sticking out of the back of the clutch pressure plate. Pull knob out and rotate the adjuster plate clockwise if the clutch needs tightening (lever moves all the way back and the clutch still won't pull the load) or counter clockwise if it won't snap in. Move it a few holes at a time and then try the lever again until you get it snapping in with a good firm pull. Put transmission in gear if the adjuster is difficult to move, that will hold the clutch still for you.
Since your clutch worked recently and now it won't, I am guessing something has changed. Could be just the rust is worn off the pressure plate, or a piece of clutch lining could have "stacked" in between the pressure plate and the clutch disk. Or the teeth could have stripped off the outside of the clutch disk.
I seen what you are talking about with the adjustment's I'm sure it was rust hear are some pictures I'm going to try and adjust it today![]()