Hi Fitzy, the SB 590 cylinder reel and rear roller work in tandem...ie. you can't have one without the other.
You squeeze the clutch handle, the bell-crank over-centres; the belt tightens, and away you go, cutting grass and self propelled. You have not got the luxury of a cutter-clutch.
If I were you, I would wait for the Model 45, which is a better all round machine, and all parts are readily available; whereas the 590 is harder to work on; (especially the reel to bedknife adjustment).
