I was recently given an old 610 - after a bit of cleaning and lots of WD40 - things are moving and it actually works....mostly. I have a manual ordered but I was wondering if someone could help identify what the small pedal on the right side (next to the bucket tilt pedal) is for? The three larger ones are clear to me but I have not explored the smaller one to the right yet... Any info is grately appreciated. Looking forward to playing with this old girl!